Sherryjune, I was a non-practicing christian (fallen away Mormon, really) when I met my Catholic husband. The entire time we dated, and for 2 years after we were married (I didn’t convert until we had been married over 2 years!) I would just sit silent during prayers, and during mass, if I went with him. I didn’t like it though, I felt disconnected and left out. Even if I said my own inner prayer, it wasn’t the same. There is absolutely nothing wrong with wanting to participate in their prayers, regardless if you’ve never prayed that way before. I’m sure more than anything, he and his family will regard it as a sign of kindness and respect if you do! In other words, brownie points!

LOL But seriously, it couldn’t hurt, and if you want to - then do it!
If you are considering joining the Catholic Church because of your son (I joined because of my kids, too! But I’m SO glad I did!!) I do highly recommend start attending mass on Sundays, talk with a Priest and inquire about RCIA. I loved going to my RCIA classes because I learned so much, and I had the opportunity to have every question I’d ever had about Catholicism answered, one on one.
Also, if you were married before, don’t stress out too much over the red tape. I was married before too, but thankfully our parish priest didn’t require me to get an annulment, maybe because at the time we were married I was not a Catholic, and my previous marriage had taken place at a JOP and not “under God”.

It’s just a good idea to ask about these things now so you know what to expect.
Good luck!