Wow, this is crazy interesting!
Unless it's just some "coincidence" that she has now ran into you three times, I'd say chances are very high that she's very interested in you. Because this is very rare for a girl to do, follow you, including to a GameStop of all places. It's very common for a random girl in a public place who thinks you're hot or interesting in one way the other to casually give a smile or intentionally-unintentionally try to get you to notice her. When such a thing happens to me, I can go for weeks without being able to get it off my mind. But these are only one-time things and your case seems to be more. That level of interest could be anywhere from just thinking you seem really cool (like she's starstruck by you) to that she's stalking you and maybe knows your name and has looked you up on Facebook.
What are the numbers, the chances it's a coincidence? Do a lot of people go to your school, ride that bus, frequent that GameStop and café? If it seems too low for this series of events, then you may indeed have yourself something of a secret admirer. Remember that it's always better to feel your way through courtship than to over-think it. If you're getting a strong vibe from her, act on those feelings - use your heart for power and then filter your actions through your brain, through your judgement. Will you regret it if you don't?
God, I would be blown away in such a situation! Normally it's unexpected for people to start hitting on each other in a public place and I probably wouldn't do it but this story just seems like a one-of-a-kind occurrence to me. A hot blonde girl following me - it sounds like a dream come true and a nightmare at the same time. Because if you see her again, and she's staring at you again, it would be a mistake not to introduce yourself. But it could easily end up being in some confrontational and awkward way. The first words would be the hardest, if you're at the frickin' GameStop again maybe make a comment to her about video games, but that sounds pretty nerdy. If you're at the café it would be a lot easier, maybe ask her what she's having to drink and if she goes to your school - and then say something like "you know, I think I've seen you before. My name is [Abcrone], nice to meet you".
Best of luck man, like I said I'd both love and hate to be in your place. I'd be obsessing about it with almost all my thoughts, but you seem a lot less romantic or impulsive than me.
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Sagittarius, ISFP, diagnosed with AS when I was 13.
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