Nothing wrong with birthday day party. As converted Christian, we must stay undefiled from the world. 1 Peter chapter 4 . As a result, they do not live the rest of thier earthly lives for humane desire, but rather the will of God. For you have spent enough time in the past doing what pagans choose to do, living in debauchery, lust, drunkards, orgies, carousing and detestable idolatry. They are surprised that you do not join them in thier reckless, wild living, and they heap abuse on you.
Brother, Christian people can't be friends with the world. Walking in the flesh is in opposition to the Spirit. Christian people are to be led by the Spirit. We can't walk on both sides of the fence. You either walk in the light or walk in darkness. Those who walk in the flesh are disobedience to God. Those who are led by the Spirit, are in obiedence to God. James chapter 4
Ye adulterers, and adultereresss, know ye not that friendship of the world is enimty with God ? Who so ever therefore will be friends of the world is the enemy of God. This group is in rebellion against God. Won't repent and turn there backs on God. Christian people repent, study sound doctrine, and achieve spiritual growth. Its faith and obiedence to God. Christian people will suffer little persecution or verbal abuse from outsiders.
Galatians chapter 5:5. For we through the Spirit wait for the hope of Righteousness by faith. This is the ticket my friend. Be led by the Spirit, and submit to God's will. Obiedence.
5:7. Ye did run well, who did himder you that ye should not obey the truth. ? Traditions of men is in opposition to sound doctrine. It might sound right or feel right, traditions of men is contrary to God's Truth. 5:16 . This i say then, Walk in the Spirit, and ye shall not fulfill the lust of the flesh.
5:17
For the flesh lusts against the Spirit, and the Spirit against the flesh, and these are contrary the one to the other so they can't do the things that ye would do. Those walking in the flesh are in darkness, they are carnal minded. They are disobedience to God. Those who are led by the Spirit, they do will of God, they are children of light. Friends or family don't understand spiritual things or discernment. Only spiritual Christian can understand. Carnal minded people are ignorant and don't have spiritual discernment. They don't know any better. As new Christian, stay focused on Jesus and study sound doctrine, and repent daily.
I hope this helps you. Peace.