She says she like me, but is seeing someone else at the moment

Hi,

I will be as brief and to the point as possible.

Information worth knowing:
So, I am an Indian guy (just so you know) with little/no experience with relationships.
I go to a private school, and decided that in my final year (this year) I want to change my relationship status and "yolo" it.

I decided to choose a girl that I personally thought was perfect in my grade. My definition of a perfect girl is, kind, friendly, sociable, "clean" (in terms of hygiene) and decent looking.

She is 18, has a car already, very independent - which I admire.

Now the situation is this, I started speaking to her, showing I was interested etc. Everything was going well (my attraction to her was amplified as I got to know her) so I decided, I would man up and confess my feelings about her to her (which I had never ever done in my life). I did this yesterday.

I told her that I thought she was kind, sweet, beautiful and that I liked her. Thereafter I asked whether she felt the same, and I was expecting, either a yes -> then I will proceed by asking her out, or a no -> then I would have probably left her and moved on. Simple enough right? Her answer was interesting and really confusing to me (if you ask me). She said that she DID in actual fact feel the same about me. She said she enjoys my company, etc. I continued and asked her out BUT then she proceeded by stating "BUT, I am already seeing someone." To make things even worse, she then said, "if something happens, I will ask you out." (in a sort of giggly/laughing tone) After that, I was absolutely shocked because, I 100% thought this was not a possibility, I checked what I thought would have been sufficient to determine if she was single (Instagram bio and posts, Facebook posts and relationship page) but obviously I was wrong.

After some thinking, sleeping, and I'll admit, some tears, some questions arose. I think it is worthwhile to note, she had asked me before if I was writing an exam today, and I was, and to my amazement she actually sent a message to me wishing me good luck, however, she used my "full first name" instead of the nickname she normally uses.

What really confuses me, is if she has feelings for me, then how is she going to still stay with the current guy she is with?
Secondly, she said, "if something happens". Did I just become the "backup" guy? Or could she have been meaning something else?

I genuinely like her, and from what I have seen, I have deemed her "trustworthy" but is it at all possible that she lied? Could she not actually be seeing somebody and are the feelings she has for me legit?

I am not sure what exactly what the next step is. I was thinking of something like, talking to her again, and asking her just that subtly. If her feelings are legit, must I sit around and wait for her? Must I stay friends with her? Initially I showed her my interest by doing things that I would NEVER ever do for a friend, sweet and thoughtful things. Most importantly, I feel it is WRONG for me as a guy, to continue making conversation with her, since I like her more than just a "friend" while she is already "seeing someone." At the same time, I really like her...

This entire situation is a **** up because, I would have NEVER went for her in the first place if I knew she wasn't single, and now, I put her in a difficult situation. Now I am hurting (emotionally drowning), she feels bad (from what I assume with sending me a good luck message), and now, I am also in a tough situation.

Help me please :/
Thanks in advance

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