HELPME!?!?

Me male (15) her female (15) OK so there is this one girl in some of my classes. I have known her for about 3 years and would like to start dating her but don't know how to ask her out.We talk a lot and she tells me her problems and has even cryed in front of me. But I don't know how to ask her out even tho I think she is giving me sign's. like she always want to sit with me at lunch and wants to be close to me. I am aware of the people she has dated and (not to sound egotistical ) I am a lot hotter. (6'2 210 pound's and I do wressaling the bulk went well) I just don't know how to aproch her without being creapy. I have dated before 2 time both lasting well over 2 years. but now I am in highschool and idk why but list a lot of confadence.