My opinion overall of dating someone with children --
It's hard to do. It's hard enough having a relationship with someone and developing those interpersonal / emotional skills. Being on the spectrum makes it even more challenging to be in a relationship, although of course it's not impossible and many people manage to build strong partnerships with a lot of time and patience.
Adding a partner's kids to the mix can be tricky. That means you will need to form a relationship with each child separately, with the children when they're together (it's different than separately), with your partner, and even with their ex if that ex is still in the picture. Don't forget the ex's family. It stands to reason your partner will always put their children first, and the children will be their first priority. If you have your own children it makes even more relationships which you'll need to juggle (your kids plus their kids, individually and as a group). It's a lot of juggling and a lot of sacrifice. Your kids might get jealous of your time with the partner, or with the other kids, and it's very expensive too (family meals, family vacations, special needs).
I know you don't have your own kids, but it's something to think about. There are lots of blended families and successful stepparent situations. I applaud those. I'm just saying that it's a lot of work, with a lot of variables that will change almost day to day as the children get older, and the partner goes through different stages of cooperation / fighting with their ex.
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I never give you my number, I only give you my situation.
Beatles