yesbody even if u do convert to Islam will u be able to do full justice to it? i am sure u want to convert just because u love her and you will DEFINITELY turn back back to ur own religion once u get her cos its hardwired in ur brain because of the faith u were bought up with. Allah will not forgive you if u do such a sin.why do u want to incur His wrath? i suggest u think over it and if u do convert to Islam stick faithfully to it or else marry the girl in whichever religion u r.intercaste marriages happen a lot in this world so dont worry.