Hey guys need quick advice:

I (28) had a 1. date with a girl (23 or 24) last weekend and we made out a lot and laughed alot so I think it went good. A few days ago I asked her if she wants to meet up this weekend and she said "sure friday or sunday?" And I chose sunday. Now she texted me if we can do sunday because her work collegues want to go for drinks today (she leaves the company in a few weeks). Is this a flake? Is she not interested enough? How should I respond?
If i am honest it does not even bother me because I can go and play football now but the reason bothers me a little bit (it is not an emergeny). Other problem is that if we do it on sunday the chances of her coming over/staying over night at my place is slim bc of work. Thank you guys!