How to deal with being ignored?

Just ignore it, I know! But I still like to hear what people say.

I am an Asian immigrant who has lived in the US for 20+ years, and there’s one thing I am still not wholly feeling comfortable with: people are often ignoring others. Not only online, but in real life too. Here is a recent case that makes me wonder:

I moved to a new community 1 year ago and started being friends with a neighbor. We occasionally exchange food, have casual conversations, etc. She is a middle-aged single, so a couple of days ago I sent her a message asking her if she likes to go to a park with us. No response, no explanation whatsoever.

I would totally understand that if she says something like “no I already had a plan but thanks”, but nothing. Not sure if I am somehow a different creature, I myself have never done such kind of thing to anyone, because I would imagine if so how the other one would feel like. But unfortunately being ignored seems to be one of my American experiences with which I am still learning how to deal.

I am 50 + year-old so I understand we need to take this kind of thing lightly. And I also know this happens everywhere, not only here. However, compared with the country where I came from, I experienced this type of behavior much more frequently here in the US, so I think it’s fair to say this is a cultural thing. My question still remains: is ignoring people’s invitations/requests/questions totally OK in American culture? Have you ignored others? If so, what made your feel OK with that?