Heya, and welcome!

Many many here started riding late, many are much older than you are. And I think we must have heard about every question there is to ask :-) So bring it on.

A few points that may or may not be useful:

beginners improve at different speeds. Don't be discouraged if you find your husband getting stronger and faster quicker than you, he's got testosterone on his side... Try riding just with your kids sometimes, or with other friends every now and then. Don't obsess about speed! There's ALWAYS someone faster and fitter than you are. But they aren't necessarily enjoying the ride any more :-)

your butt probably will hurt to begin with. Part of it is bruising, or sore sit bones, which feels like two very sore spots right where you put your weight. It goes away fast, after a week or so. If you're still sore, or get chafed skin, you probably need a better saddle. Lots of info here on this site. A good saddle and good quality bike shorts are really important if you want to keep riding, if you're uncomfortable most of the time it just won't be fun.

do wear a helmet, and make sure it's snug but comfortable.

the weight of your bike does matter, even though it may sound odd that a lb or two is noticeable. Nothing to obsess about, but it's not all about the strength of the rider.