What do I do!

Mom started dating this guy about 2 months ago... He's more my age than hers... And he's fucking hot 🔥🔥🔥🔥 and last night when she went to bed early he grabbed my ass and kissed the back of my neck...... I wanted to fuck him so bad right then and there but we both walked away.. Ugh what do I do? Fuck him or let it be???