Guys who have started MMA careers in the second half of their 30’s or even later usually have a somewhat accomplished background in something. There’s a few examples of guys with wrestling backgrounds that have been able to transfer their skills over quite well. A lot of being naturally athletic, and then they end up being good at striking also. 

Not everybody is gifted with natural athleticism and this means you’ve really got to put the work in, especially if you’re starting from scratch! A full fledged MMA career may not be completely realistic, but this doesn’t mean you can’t start training, and then see where it takes you.