Just show up and try it.

Back when I was riding week night crits, the “B” packs weren’t that tough and I could sit in, no problem, as a very casual racer. I rode cautiously and didn’t do well, but I certainly had fun. I was in medical school for four years of my racing “career,” such as it was, and couldn’t have done more than a race a month.

As as for the risk of injury, it is real and I wouldn’t do it today in my 7th decade, but back then it felt fine. I saw a few crashes, but nothing bad happened to me.