I have an obsession with this girl? Is this a problem?

[surfhb]

It means you need therapy and refuse to do so

You're also a troll

[extremis]

It means you need therapy and refuse to do so

You're also a troll

I'm not a troll. I said before I don't talk to anyone about this in real life. Talking online is the only way to get it off my chest. Yet no one is giving any tips to how to end the feeling

[searock]

it is some kind of problem I should tell someone? Or will it go away soon?

I'm not taking to any therapist about this. I don't want to make this a big problem and then I would probably have to tell my parents

You answered your own question. Seems like you don't want our help after all.