God will welcome you but your parents or others might not.
There will be no punishment from God for this.
From other people, not that i know of. I know for a fact God would not punish something like that as a growth in relationship to Him
Yes, you are an apostate and under Islamic Law this is punishable by death. Interesting concept, since Islam, Judaism and Christianity all share the same God.
IT said on wikipedia that it is something which can be punishable by death but I feel that this is an exxageration for Islam and Christianity are both from the same god so it's a different method to how you worship god