Welcome, julie!
I've picked up cycling within the last year or so and definitely am not the fastest. I just mentioned to someone on another thread that I've found that the VeloDCity Meetup group is a great place to get your feet wet. I joined them for a couple of rides last year on my hybrid and always found myself pretty much in the middle of the group. The rides are no-drop and it's a good way to introduce yourself to group riding and other places to ride in the area.
You sound like you are in more shape than I am but I'd be up for a ride as well!