No extracurriculars or AP classes

You can include your babysitting as an extracurricular. If it took a lot of time and let's say you had to cook clean and manage a lot of the house things a lot of applications allow you to write that down because a lot of students who come from lower-income families with bigger families aren't able to join these extracurriculars because of responsibilities at home. It wouldn't necessarily make your chances go down but I think you should put babysitting as some type of extracurricular. For example, you can make it as a job or you could say that you babysit. And specifically about the AP classes if your school didn't offer any APs you're fine. But if your school offered AP classes and you didn't take them it does look bad on your part on the application because you could've taken something more challenging unless you took an IB class or your school's equivalent of the highest possible class.

There should be somewhere on your application where you could say that you couldn't take any EC's because of responsibilities. As for AP it should only matter if your school offers some. I think it would balance out a bit with your family responsibilities since they require more time. I will say you should try to work on enhancing your EC's. I'm in a pretty similar boat as you except instead of babysitting it's working for my parents as an intern basically. I recently learned that you could turn seemingly simple stuff into an EC. I like crafting in my free time so I found an organization that sends handmade cards to hospitals. Crafting is something I would of already done so instead of just making something random I'm going to start making cards. My classmate likes knitting so she started making hats for cancer patient kids. By themselves just saying I like knitting it isn't something tangible but with a little digging your non competitive hobbies could turn into something.