Translation:יש לה אפרסק.
is this correct? לה יש אפרסק
Only if you wanted to stress that she, not someone else, has a peach.
Is "לה" the feminine version of "לי"?
No. לה means "she has"/"to her". לי = "I have" /"to me". One could say לה is feminine version of לו which means "he has".