Here are listings for age restricted 55 and over communities in my service area from the MLS. 55 and over communities are NOT a good choice for investors because many have rules prohibiting new owners from renting their units for to up to 2 years after purchase.
In FL, to qualify to be a 55 and over community, at least 80% of the association members must be over the age of 55. Usually, a person under this age will have no trouble buying in this type of community. However, you should be aware that most if not all 55 and older communities may not let you stay in your own condo if you are under 55, or will limit how long you can stay during the year. Most communities have rules governing the age of visitors, and most are pet-friendly for owner occupants with small pets.