I have had a person challenge me with something similar. The scripture is very clear that God loves his son and gave Christ to be the sacrifice for our sin (John 3:16), that Christ is God's gift of redemption, and that God is pleased that all fullness (salvation, life, health, joy, peace) should dwell in Christ and be ours through belief in Christ as our savior. Worship of Christ is not offensive to God; it pleases God when we acknowledge Christ as Lord and worship him.
I have done some study on this, and here are scriptures which bear this out:
2 Corinthians 2:14- “Now thanks be unto God, which always causeth us to triumph in Christ…”
2 Corinthians 1:21- “Now he which stablisheth us with you in Christ, and hath anointed us, is God.”
1 Corinthians 15:57- “But thaks be to God, which giveth us the victory through our Lord Jesus Christ.”
1 Corinthians 11:3- “But I would have you know, that the head of every man is Christ; and the head of the woman is the man; and the head of Christ is God.”
1 Corinthians 3:23- “And ye are Christ’s; and Christ is God’s.”
Romans 6:23- “For the wages of sin is death; but the gift of God is eternal life through Jesus Christ our Lord.”
2 Corinthians 5:18- “And all things are of God, who hath reconciled us to himself by Jesus Christ, and hath given to us the ministry of reconciliation.”
2 Corinthians 9:15- “Thanks be unto God for his unspeakable gift [Christ].”
2 Corinthians 10:5- “Casting down imaginations, and every high thing that exalteth itself against the knowledge of God, and bringing into captivity every thought to the obedience of Christ.”
Galatians 1:3-5- “Grace be to you, and peace, from God the Father, and from our Lord Jesus Christ, Who gave himself for our sins, that he might deliver us from this present evil world, according to the will of God and our Father: To whom be glory for ever and ever. Amen.
Galatians 3:26- “For ye are all the children of God by faith in Christ Jesus.”
Galatians 4:7- “Wherefore thou art no more a servant, but a son; and if a son, then an heir of God through Christ.”
Ephesians 1:3- “Blessed be the God and Father of our Lord Jesus Christ, who hath blessed us with all spiritual blessings in heavenly places in Christ:”
Ephesians 1:5- “Having predestinated us unto the adoption of children by Jesus Christ to himself [God], according to the good pleasure of his [God’s] will.”
Ephesians 1:19-23- “And what is the exceeding greatness of his [God’s] power to us-ward who believe, according to the working of his [God’s] mighty power, Which he wrought in Christ, when he [God] raised him [Christ] from the dead, and set him [Christ] at his [God’s] own right hand in the heavenly places, Far above all principality, and power, and might, and dominion, and every name that is named, not only in this world, but also in that which is to come: And hath put all things under his [Christ’s] feet, and gave him [Christ] to be the head over all things to the church, Which is his body, the fullness of him that filleth all in all.”
Ephesians 2:10- “For we are his [God’s] workmanship, created in Christ Jesus unto good works…”
Ephesians 2:13- “But now, in Christ Jesus, ye who sometimes were far off are mad nigh [we are made close to God] by the blood of Christ.”
Ephesians 3:11- “According to the eternal purpose which he [God] purposed in Christ Jesus our Lord.”
Ephesians 4:32- “…even as God for Christ’s sake that forgiven you.”
Ephesians 5:20- “Giving thanks always for all things unto God and the Father in the name of our Lord Jesus Christ;”
Philippians 2:9-11- “Wherefore God also hath highly exalted him [Christ], and given him [Christ] a name which is above every name: That at the name of Jesus every knee should bow, of things in heaven, and things in earth, and things under the earth; And that every tongue should confess that Jesus Christ is Lord, to the glory of God the Father.”
Philippians 3:14- “I press toward the mark for the prize of the high calling of God in Christ Jesus.”
Philippians 4:7- “And the peace of God, which passeth all understanding, shall keep your hearts and minds through Christ Jesus.”
Philippians 4:19- “But my God shall supply all your need according to his riches in glory by Christ Jesus.”
*Colossians 1:12-19-
12 “Giving thanks unto the Father, which hath made us meet to be partakers of the inheritance of the saints in light;
13 Who hath delivered us from the power of darkness, and hath translated us into the kingdom of his dear Son [Christ]:
14 In whom we have redemption through his [Christ’s] blood, even the forgiveness of sins:
15 Who [Christ] is the image of the invisible God, the firstborn of every creature:
16 For by him [Christ] were all things created, that are in earth, visible and invisible, whether they be thrones, or dominions, or principalities, or powers: all things were created by him, and for him [Christ]:
17And he [Christ] is before all things, and by him [Christ] all things consist.
18 And he [Christ] is the head of the body, the church: who is the beginning, the firstborn from the dead; that in all things he [Christ] might have the preeminence.
19 For it pleased the Father than in him [Christ] should all fullness dwell.”
1 John 4:10- “Herein is love, not that we loved God, but that he loved us, and sent his Son to be the propitiation for our sins.”
1 John 4:15- “Whosoever shall confess that Jesus is the Son of God, God dwelleth in him, and he in God.”
1 John 5:5- “Who is he that overcometh the world, but he that believeth that Jesus is the Son of God?”
Keep this in mind, if you discuss this with your friend, unless your friend is open to the Word, he/she may still not accept that God gave us the gift of Christ for the redemption of our sins and it's God's will for us to worship Christ as our Lord and Savior.
However, you stand strong in what you know to be true- that God is not jealous of Christ. Christ testifies of all things to the glory of God. He constantly acknowledges the glory of God. God has saved us through the blood of Christ. God gave us Christ and Christ gave himself as a sacrifice for our sins. You never have to be ashamed or questioned for worshipping Christ as your savior, because you glorify God when you do so. Nobody but the true and living God could create a redemptive plan of salvation through Christ.