How hard is it to learn on a fishboard?

I'm 5'7 weighing 115lbs, and I can borrow a 6'8" long, 20,5" wide, 2,5" thick fishboard for free.
I know mals/longboards are the otpimal beginnersboard, but since I'm quite small/light, (and don't have the option to borrow any other board too) would it be a totally hellish struggle trying to catch some smaller (waisthigh at most) waves with this board for me? I'm not afraid of being wiped out for hours for days in a row...
fishes are supposed to be real "loose" and all, but its pretty big for being a fish right?
whaddya think?
I know mals/longboards are the otpimal beginnersboard, but since I'm quite small/light, (and don't have the option to borrow any other board too) would it be a totally hellish struggle trying to catch some smaller (waisthigh at most) waves with this board for me? I'm not afraid of being wiped out for hours for days in a row...
fishes are supposed to be real "loose" and all, but its pretty big for being a fish right?
whaddya think?