No support from teenage coworkers

I apologize if I do offend anyone. I really like the people I work with and don't want any bad vibes to them but I just have to vent about something.

There are two instances where I stayed way past my shift ending(like an hour later). The first instance was one day a couple weeks ago. I was having a bit of a rough time being alone because I was feeding two babies at once and the room was a wreck from the older babies. They sent in someone to help me but all she did was sweep up some cheerios from snack time and take my babies to their parents. She helped close another room and then left. She had mentioned she needed to be out by 5:30 for a very important dinner with her boyfriend's family. I mentioned that I'll probably be there until 7 because I had so much to do and one of my babies doesn't go home until 6:30. This baby also takes a very long time with her bottles(anywhere from 30-60 minutes). She didn't help with anything else so once my last baby left I was able to start cleaning everything as it was Friday.

The second instance happened today. I had to merge with the other infant room because the employee over 18 was leaving so there was just a minor in that room. She asked me if she could go clean her room and I was like,"sure, yeah." Mind you one of her kids was crying and wanted to be held as all her needs were met except for attention/love. Therefore I held her as well as one of mine because they were both crying for attention/love. After her kids left she left after cleaning her room. Didn't offer to help clean some of my room or at least hold my needy baby while I cleaned up a little.

Both of these people were teenagers and the girl who normally closes the other infant room is over 18. I'm not trying to point fingers but both instances were teenagers. I know the second girl wasn't instructed to help me but I just feel like she could have helped me a little since I watched her babies while she cleaned her room. Am I asking too much? Should I just mention it to them? How do I approach teenagers with this concern? Idk man I'm sorry if I sound dumb it's just been eating at me and I'm sorry if I didn't clarify something. Any advice is appreciated