Say I purchases a house in a +55 community, but am under 55 years old. This is because there is a law saying that at least 20% of those who purchase in such a community CAN be under 55. I believe this is so that they cannot be accused for age discrimination.

So, upon re-selling my home. Could I sell it to whomever I wanted to? Would the purchaser have to be +55, or because I have the deed and am under 55, could I likewise, resell it to someone who is under 55 years old?

It would make sense to me, I could sell it to anyone (including under 55) because it would be upholding the same 20%. Is this true?

In addition, could I market the home by saying that this is one of very few homes actively listed in this +55 community -- but the purchaser does NOT have to be 55? Thoughts? :confused:

The rules of advertising real estate is very controlled. So you need to actually verify with the HOA of he community as to your states specific rules. The issue could be if they lets say are now over 20 percent, and in that case you may be restricted. I would say I would use a real esate agent and let them handle all of the advertising.

So... Ask a realtor?

there is a law saying that at least 20% of those who purchase in such a community CAN be under 55.

There are two things about the law you cite. First, whether it applies only to initial purchasers not resales. Second, your emphasis on the word CAN. CAN is different then must. Sales in such a community might be subject to approval by an HOA so you need to check with them first.