im scared to cum! :/

Okay, here it goes.i have alor on my mind im a 13 year old girl and I masterbait almost every day is this a problem?? also, when ever I do masterbait, and im about to cum I chicken out and feel guilty!!!! I dono, if im doing it right and can you give me some tips on making it better?? Im also addicted to lesbian porn, and I think im a lesbian, r maybe bi?? Please help!