How do I tell my gf I love her?

Idk if this is the right subreddit, but I'm too afraid to ask anyone else so to this sub it is!

I'm not disclosing our ages for privacy, but we're both teenagers so that's why I'm a bit nervous. She's my first gf ever and I really, really love her. We've been dating for 2 months and we kiss and cuddle, but we haven't said the big three words yet. She's coming to my house to sleep over today and I really want to tell her then, but I don't know if she'll say it back? My friends say "I love you" to their partners and they told me that it wasn't as big of a deal as it's made out to be, but I'm still nervous- stereotypical teenage feelings and all that. I don't want to seem overbearing or over affectionate, I don't want to drive her away or creep her out or anything, and I'm scared I will.

Any tips for how to tell her? Is it too soon? Ughhh idk