Why does my friend keep asking to hang out and then bails last minute?

So my coworker (we’ll just call her A) who is also said to be my friend, she does this really weird thing where she would always invite me and my other friend (friend B) to hang out but what is weird is that she initiates plans ALL the time and then last minute, she’s with somewhere with her dad or she’s trying to go have sex with some random guy and she’ll ditch me and friend (B). I get that things come up but it’s a common cycle of her doing this and it’s really starting to piss me off and not be her friend at all anymore.

Another thing that makes this situation weirder is that she doesn’t even own a car! Not that having a car isn’t necessarily a bad thing but she makes plans and expects me or friend B to drive. by the way, if it matters, friend A is 18 and my and friend B are both 20. I just don’t know if I can handle the immaturity of an 18 year old. I also hate people wasting my time. The last time we all made a trip and both of them made some shitty excuses as to why they couldn’t go. I hung out with friend B once and then friend A completely ditches both of us because she “forgot” about her brother’s birthday party. I’m not sure if I’m overreacting or not but it just seems to me that Friend A, the one who doesn’t have a car likes to make plans and she expects one of us to drive her around and what pisses me off is she doesn’t offer gas unless I speak up.

Yesterday again, friend A asked in the group chat if we should all hang out and honestly, I’m not interested in hanging out with them anymore because I feel like my time isn’t valued.
I’ve began going out alone and honestly I feel quite fond of it. I’m just wondering if I’m doing the right thing by leaving them both alone?
Why does my friend keep asking to hang out and then bails last minute?
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