<human>: Can you provide a brief overview of the text?

Me and my girlfriend have been dating for almost 2 and a half years. Overall I would say we have a very solid relationship. We've had our ups and downs but came out on top together. 

So yesterday was the birthday of my John, one of my good friends. He planned on going out during the day with other friends but I couldn't make it due to work and could only come after 6.

My girlfriend is also friends with John and went out with the group during the day. I meet them back at Johns house and we all hang out for a bit and things are great between me and my gf. 
She's sitting with me and we're talking, you get the gist, trying to say things were good. 

So I waited till my girlfriend wanted to go home to drink or anything else and while I was driving her home I asked if she would like to hang out tomorrow and she said yes.

Now I said how about 2:00 because we would be drinking and possibly smoking and staying up late and I didn't want to have to wake up super early. She knew we would do this as well. She then says that's too late how about 12. I say I can try and make it but I'm not sure. 

So fast forward to today and I wake up groggy and see that it's 11:30 I get up and start getting ready at my friends house( I have lots of clothes that I left there that went through the wash and decided to leave them there as spares. 

So I get a text saying where am I around 10 minutes later from her and I say I'm just getting ready and then leaving. She seems very upset. I would have probably got there around 12:15 at the latest. I try to figure out what's wrong or apologize but she keeps getting more upset and just stops replying saying lastly how I'm always late and I obviously don't care. 

I've tried calling her numerous times and texted her, I'm just gonna let her cool off and have her space.

Any thoughts? Am I being inconsiderate?
<bot>: After a night of partying for a friends birthday I wake up late to hang with girlfriend, she's upset and won't respond.