I refer to the letter I have never been a Muslim by JV.
Islam is very clear about the faith or religion. The Quran clearly says 'There is no compulsion in deen (religion)'. It is your choice if you want to leave Islam and convert to some other religion. Islam does not put pressure on any one to not do that.
You say that you have never practiced Islam in you entire life. It is not strange, there are many Muslims who have never offered even a single prayer but they call themselves Muslims.
My advice to you will be before converting to some other religion, be brave and honest to your self, read the Quran with full understanding and after that if you still feel you want to leave Islam, then it is your choice.