Age has never been an issue with me. However, sometimes you end up in those classes and the group of women either don't click, they're focused on using the scheduled time to catch up on their own stuff or they are in such a tight clique that you end up being an outsider. Some days I would socialize, other days, I would catch up on paperwork, menu-plan, write letters, etc... I have found interesting moms in a variety of ages. So many times, if the conversation or group was interesting - I could sway myself to jump in and figure out another time to juggle my responsibilities. The common ground that you have, when children are about the same age, opens the door to meeting people. That doesn't mean that the moms will necessarily be nice, welcoming or socially available. It is WHAT it is!
Please, please, please, keep making that effort. Keep throwing your pleasantness out there. You are going to touch the right person's heart and make that connection. Be a good listener and be interested in others. Ask lots of questions, initiate conversations about hobbies, newsworthy items and recipes and get people talking about their favorite subjects - their children, their families, themselves! Invite a few over for sandwiches when the weather gets warmer. Your background is very interesting and soon, people will be all over you, seeing a poised responsible person, (listening to your accent) and will be interested in your history, life and friendships will be created.
If this group won't budge... then, move on. Get involved in the library programs or move on to other "mom/tot" groups through religious affiliations. You will find your niche of friends and, trust me, they will not care how old you are.
Have fun finding those friends.