Pretty much I don't understand women and think they are irrational. I will explain my story and hopefully someone can enlighten me on how this girl is thinking during each stage of the story.

6 months ago -
A new girl enters my friend group.

4 months ago -
I develop a crush on this new girl and confess my feelings to her. She says she just wants to be friends. We end up hanging together a lot more than before and also hung out more 1 on 1. I become her best friend in the group.

I've been told that you should never confess, it destroys the challenge and the girl will think you're a creep. I don't understand why we ended up hanging out more. Maybe she just didn't want to hurt me or she felt obliged for some reason? Whenever we hung out she always made sure she payed her fair share and never asked for anything in terms of favors. Probably so she knew she didn't owe me and that made it easier for her to leave at anytime without guilt? Also she is an independent person and it might just be that she values her independence

1 week ago -
I text the girl that there is a party with the friend group. She replied that she doesn't want to hang with THOSE guys anymore. She also became less responsive to my texts.

My initial reaction was THOSE excluded me but after more thinking maybe she just didn't want to be direct and in actual fact it was directed at the entire friend group including me. The reason for her leaving? I can only think of 2, she finds us boring or she thinks I'm a creep. I haven't made any moves on the girl since confessing but maybe she still feels creeped out? There was no conflict between her and any member of the group and I know she just met some new friends

today -
It was her birthday and I had already bought her a present so I decided that I might as well give her the present since I've already bought it. After giving her the present she starts texting me again saying we should hang out again. She's already suggesting activities for us to do. Kinda weird going from no contact to the most contact I've ever had from her.

What does this mean? Is she interested in me all of a sudden or is she just trying to be nice? ie she doesn't want to owe me anything so she can move on without any guilt? I also hit her up about the "not hanging out with those guys comment" and she said it was just her being stupid and that she didn't mean anything by it.

What should I do if I do decide to hang out with her? If the answer is to kino escalate then I'm kinda scared cause I don't want to creep her out again.

Dude you're overthinking this to the 9's!! Ya its not best to tell confess your feelings to her, but if she was creeped out by it she wouldn't have hung around as long as she did especially not 1 on 1. What girl would hang 1 on 1 with a guy she thinks is a creep? Did you do anything aside from telling her your feelings that would creep her out or do anything to think you're the reason she didn't want to hang with that group anymore? If not forget about it and if you did it was a mistake or misinterpretation and she's over it because she said she wants to hang with you again. If you want this girl as your gf take this as your second chance be the alpha male be confident and direct. Don't text her CALL her! Have a strong convo that will be more effective than any text you send her. End it by saying so how about you and I grab a drink tmrw night at such and such place say 9pm?? ( That's just an example suggest whatever date activity suits) and go from there if you play your cards right she'll start seeing you as potentially more than just a friend. I've been there before friendzoned took a break came back a better guy better skill set and it was like I was never friendzoned in the first place.

That sounds positive. I am a guy with zero game. What do I do now? Also how do I skill up quickly?.
Looks like my first task is to get a date. The girl has already set up a sports game to go to together but it is 1 month away.

your life resolves around this one girl. sorry but you just dont have the social skills or attractive traits yet to get this girl. but do not get discouraged there are more and other attractive girls out there.
you need to take proactive action, learning cold approach , day and night to get your social skills on par. date some, get experience and comfortable being around girls.