I've started to like a girl, and i'm a girl,does she like me?

I've never liked a girl before... Is it normal? Is anyone else in my position??

How do I know if she likes me back? She doesn't talk to me about sexuality, so I don't know what her preferences are.. I'm not gonna go into details, but she's been showing a lot of signs she likes me, she's always in a good mood around me, always laughing and smiling, and her smiles don't go away fast either.. and is wanting to be around me more.. Texts me quite often,usually about something specific. I wasn't in school all last week and she was texting every day.. and teasing me a bit. I lost my voice, and she was teasing me about getting me a year 8 group to look after in school (which would be a nightmare, i'm 17 btw)And she was only joking but I was like 'i'm not speaking to you if you do!' And the reason i was off school was i'd lost my voice.. So she text back 'you can't speak anyway :) Yesterday, she text saying 'please tell me your in x' and i didnt reply because I didn't check my phone, and then today she text saying 'Are you in :) ? X' and she was sitting with my friends at break. She doesn't even know them that much, so why was she sitting with them? I didn't text back, but I was in the other room catching up on work and didn't get it! And didn't know this till later. She asked why i didn't text back.. She just shows a lot of signs in general that she likes me as more than a friend, I mean we have this session where 3 of us revise for our last year chemistry for resits, and because i was off all last week, she ditched her friend(I thought she was better friends with the other girl) to help me out, which was of no benefit to her studies. So it was just me and her, and the other girl just went elsewhere.. What are the signs she likes me so i'll know?? There's loads more things I could put down but I don't want to go on and on.. Thanks