Does she like me? Should I ask her out?

Ive known this girl for the whole school year, well..one day..i schedule a drive with her and she gets really excited..she gives me her number and shows me 100% signs of liking me that day (i didnt ask her out because I didnt want to risk the friendship.) i once asked her to hang out over spring break(sometime after her cruise). she said she would text me and never did. then we had a distant time period, but we are pretty close again. we have talked a lot the last few days, and I finally have asked this girl if she would like to meet up for lunch sometime over the weekend. We both just got our licenses, and I I talked to her over the phone on friday, and it went really well. said she would text me later for details and such. she never texted me, but im confused.. By the tone of her voice, it really seemed like she would like to hang out with me. i saw her in school today and we seemed to talk fine...i sat next to her at an embly and i noticed that she looked at me seldomly...and when we were walking down the bleachers at the end..she was holding onto my back/shoulder..does she like me? or what? sometimes i get the feeling she doesnt really want to talk to me because she may seem nervous..idk though. im confused. we sometimes have "silent moments" in our conversations on the way to cl(we walk together everyday). thanks! i really just want to spend some time with her by the end of the year... i have known her since the beginning of the year...and im afraid that i wont see her over the entire summer..what i basically want to know is...should i tell her i like her as school ends? i know i should have asked her out 2 months ago when she was showing signs...do you think she may still like me? thanks a bunch!