Religion is worshiping something. It might be Allah, Satan, money, yourself, some patriarchal figure, or even Jesus. If your religion is about worshipping Jesus, then it is probably a form of Christianity. If you worship some watered down or distorted figure that you like to call Jesus, then it is probably something else. However if you are worshipping the real Jesus of the bible then what you have is probably Christianity.
Some religions find buildings and rituals to be important.
While there is nothing wrong with buildings and rituals, they do sometimes become a distraction - and some people become more interested in worshipping the buildings and rituals than in worshipping Jesus. Big religions sometimes need lots of administration. However you do it, worshipping Jesus is a religion. Remember, though, worshipping Jesus is a lot more than singing hymns and kneeling down. It's about the life you live.