Which 125cc learner legal bike would be good for young small rider,5'5'' to be exact?

go for a honda 125....also go for 2nd hand...unless you mean to keep it a very long time..i did my cbt on a yam..bought a honda 125 (new) built up my long forgotten road skills..6 months later took my test..bought a honda cb500(now long gone..but lost quite a bit on the 125 even trading it in against the 500.....)so if you intend to have it forever buy new..whichever make you decide on..ride safe bro.p.s.im assumming you are uk based....