Healthy weight??? exercising?

i am about to start kickboxing..and it helps u lose weight...i am not sure if i should lose weight or not or i should try to build muscle.. i am a 19 year old female...and i weight 105 and i am 5 feet and 1 3/4 of an inch...(i guess 5 feet 2 inches) and i wanted to start kick boxing to tone up...should i try to lose weight as well?? whats my ideal weight?