Having feelings for girls doesn't seem like a phase, at least in my experience. Plus you don't have to figure it out today (it's completely fine to be unsure) because I know I, and many others, had a hard time with it at 14. Right now, you don't even have to label yourself. You can just say: "I think I might be interested in girls," like you're doing right now. Labeling yourself as "bisexual" or "gay" can be pretty frightening at any age, especially if you live in an area where homophobia is considered the norm. Even though it may be frightening, I would consider not to brush off your feelings as a phase. Doing so makes it harder to analyze your feelings.
Regarding confusion, here's an anecdote: When I was 14, I thought I was bisexual, and then, the next year I thought I was lesbian. I was extremely confused, and it was frustrating. When I turned 18, I finally made a concrete decision regarding my orientation and ended up labeling myself bisexual. To this day, I still label myself bisexual, but I don't date guys. The idea of being romantic with a guy makes me want to puke sometimes, but thinking of having sex with a guy sounds nice. With women, I love having romantic and sexual relationships with. That confuses a lot of people, but it explains my orientation, which is, specifically, homoromantic bisexual. As you get older, analyze your feelings. You could ask yourself: Are my feelings purely sexual or romantic for a specific gender? Do I have feelings for men and women (note: the feelings don't have to be equal in intensity)? Do I only enjoy women/men sexually and romantically? Do I imagine myself with a man and/or woman when I get older? When you are questioning yourself, always remember the definitions of lesbian, bisexual, and straight. This seems obvious, but when I was questioning myself, I got lost in the definitions when trying to figure everything out.
Lesbian - only women, Bisexual - women and men (doesn't have to be equal), Straight - only men, in this case
Plus keep on checking out this sub, and consider looking at /r/bisexual. They both have really helpful and nice communities! I hope everything works out for you and have a good day! :D