This is a big niche and recommending a good mature site depends on what your more detailed need...
Anilos.com is a big one, having softcore, gg and hardcore content as well. Their affiliate system is awesome, easy to use and filter the content you need.
Mature.nl is another not So well-known, but old and big program with mostly Genuine mature content. Average amateur ladies-next-door rather than professionals. Lots of sub-niches like 'mature gloryhole' - these can be converted very well on proper traffic.
Anilos is easy to reach, mature.nl can be tricky, but if you stuck, I am happy to help.
Both Anilos and Mature.nl are very helpful and good people!!
