1) go to the Road Racing sub forum.

2) read the sticky on starting racing.

Beyond that, starting racing at an older age is a bit of a conundrum. There are races called " Masters" Races, which are done by age groups, typically 35+, 45+, 55+.

The problem for an older new guy is that the people racing in these Masters races are often accomplished riders (often some ex pro's and Cat 1 and 2 racers.) So they are extremely fast. Also in many areas they will not let new (Cat 5 ) racers, race Masterrs.

The other side of the coin, you can race Cat 5. Problem here is that you race against 18 year olds, some of whom ae quite fit, and many of them have no concern about being in one piece to go to work on Monday morning.

Some areas will have Cat 4/5 races for 35+. If you can find one of these it is definitely you best option starting out. Otherwise you have to go mix it up with the kids.