Does she like me?

What feeling does/did (?) this girl has/have for me? She used to 1-passively stare at me (have caught her doing that many times & even then she never stopped stating) 2-smile at me,expose her neck 3-sometimes touch my shoulder 4-try talking to me (as I would always be monosyllabic & not try talking to her) 5-I remember we were sitting next to each otheron revolving chairs,I kept on rotating(moving right-left) due to which my knees were consitently brushing past her knees(not on purpose,but subconsciously!), but still she did not object to it but on the contrary ,kept talking to me. 6-once in an elevator (that could hold 10-15 people ) only me ,her & some other guy was present,she was talking to him & I was silent(stupid me ?) even in such ample space she stood so close to me that our clothes where touching 7-once about 15-20 of us were standing & being lectured by an authority figure for some time,she on one occaison kept heading back(I was behind her) one step at a time

I know this may stupid , I also know the answer (may be) , I guess I dont have enough confidence/trust in myself. . . . .

Also I have seen that some girls keep looking at me for very long amount of time ( it has happened quite a few times) what does it mean and what should I do ??