Feel A Strong Connection Towards Someone I Haven't Met

My name is Sebastian, this is my last year of high school. My first 3 years of high school were the best worst thing that have ever happened to me, literally no friends and severe social anxiety and very low self-esteem. Year by year I got a little bit better (in relation to my social anxiety and such), this year I had a very sincere talk with a very good friend that I was able to make during this 3 years that made me decide that this year it's going to be my best year, I have no clue why but I'm 100% that that's how is going to be. Throughout all these years I've never had a girlfriend or anything like that, I've had plenty of chances but because of my personal problems I for some reason decide to get away from them, I feel like you guys need to know this because the person towards I feel this connection is a girl. We have class together in only one period, she's beautiful (being sincere not in a creepy way) I generally just watch but in this case I feel like I have seen her before. Like not somewhere else (like deep inside I feel like I know her), I know it sounds weird but I just don't know how to explain it. When I see her I feel calm, I know that when we like someone we usually tend to look a lot at that person repeatedly, and it has happened to me before because I have felt an attraction towards someone else before but with her it's different. When I think about her I feel something different, like a connection. Maybe it's me, I hope she feels the same way. Even if she doesn't it's fine, as long as she's happy I'm happy. I'm 18 and I have no clue how old she is. She might be younger than me. Another impediment. Thanks for reading.