Friend asking for hand in marriage

I'm not sure if anyone has followed my post about the friend of mines having hep C and him giving me oral.. Well I've tested negative but he has confessed his feelings for me.. We've been friends for a very long time and I never knew he felt this way.. But he's asking me to marry him! Yes I care deeply for him n since my break up I've actually started feeling more n more feelings for him which is weird.. Maybe I just curved them while I was with my SO or just didn't pay attention.. But he asked me if I would marry him by the end of the summer.. I need someone's opinion.. I don't know how to feel.. I know enough about him but just bizarre that he asked to marry me.. And so soon! Any thoughts of how I should deal with this.. Should I just go with it?