Ok so I started texting this girl from school about 2 weeks ago it was going well and we were flirting but then we became 'bestfriends' then the next day we went on a drive and we just sat and talked for a few hours

2 days after the drive we were still texting but I decided to ring her and ask her to go to the cinema but not as friends but on a date she agreed and we made plans the problems started the next day

Her:I can't go to the cinema next friday it's my mums birthday sorry
Me:wanna just go on Tuesday then? If you don't wanna go just say I'm not bothered
Her:will you not be annoyed? My dad doesn't Like me going out in the week
Me:no I won't be annoyed I'm not bothered although I do like you
Her: let's just be bestfriends then?

I agreed then we texted for the next few hours unitill she didn't reply to one of my texts so I decided to freeze her out I didn't text her at all yesterday and I don't plan on texting her today how should I get out of the friendzone and stop her from flaking because I know she mustve liked me in someday if she agreed to go on a date in the first place also how did I mess up in the first place cause I don't wanna make the same mistake again. Thanks

You reaaaaaally fucked up badly with those texts.

"If you don't wanna go just say I'm not bothered" - bad because it shows insecurity and lack of confidence.

"I'm not bothered although I do like you" - bad because you just gave it all up and removed all challenge, thereby killing all possible attraction. You also persisted to let her know that it's her world and you're just living in it.

Then...you actually agreed to being "just best friends". You definitely dug your own grave with this one. It's possible to get out of the friend zone, but honestly, you're so far into it now that it's absolutely not worth even trying. I hate to say that to people since I know it's not what you want to hear, but it's the truth. Move on and find someone else.

Yea I knew I fucked up badly I think it's cause she's from my school that I said the not bothered stuff I didn't want to seem pushy then for her to tell people she didn't want to go on a date with me but felt she had to! And you telling me to move on is the exact thing to do great advice man thanks!

Although do you think I should just stay friends with her then and stop freezing her out? Also what should I have done instead when she first flaked on me?

If you're fine with just being friends, then by all means, do it.

You handled the first flake appropriately in the sense that you offered an alternative day, but that would have been a good time to say something a little more humorous or clever. If she turned you down for the alternative day, that's when you just pick up and walk away and try again later once you've attempted to build more attraction.