What to do next about a girl i like?

i've liked her for a while, we became decently close friends and i asked her number. we walked around together when we came to school early before our regeants. we've been texting and she said "talk to you later :-)" at the end of her latest text. we have 3 more finals to go, 2 which i will take with her. i have to do something or im never going to see her during the summer. im going to have minimum 3 classes with her, honors english, social studies, geometry and i dont know about lunch but im hoping to have lunch with her, possibly spanish and no electives. next year im gonna start getting closer to her right away. i started talking to her the last 3 weeks of school, and instantly fell in love with her personality. i think we're good enough friends to go out together. i have her phone number and if i dont ask her out during school, how often should i text her? id hate to ask her to hang out together over the phone but if its my only option ill take it. im just scared that i'll never see her during summer if i don't let her know. im going to give her a big hug at the end of our last final and say im gonna miss you to show her that i do care about her. i dont want to spend hours thinking about her before i fall asleep during the summer, i want to share my summer with her instead, and tell her i really like her once school opens. im sure we'll stay friends if she turned me down, she's a really nice person. its hard to stay sane without seeing her for a whole weekend. i dont know how ill survive a whole summer. What should i do? should i tell her im gonna miss her and text her during summer and possibly hang out than tell her i like her when we can see each other everyday next school year. or should i ask her out now and have a chance at a romantic summer and an even better 9th grade year. i dont want to mess up on her. i think theres a small chance that she likes me back more than a friend. what signs should i be looking out for? what should i do next? i can only see her 2 days, maybe 3 more days if i see her during proficiencies. i need to take action but im blind with this subject and need guidence. our relationship is really developing every day and i can feel it by seeing her actions, but i dont want to take a big jump and ask her out, i want to go slow and get to know each other more and more, taking our time. but our relationship cant develop if i dont see her everyday at school. Ever since i asked her phone number, she's been nicer to me and different to me. helppp....