Welcome to Saint Louis. I moved here 26 years ago when going through major life changes myself.
I can't say for certain that Ki Aikido will get you out of your rut, but it certainly wouldn't be age that holds you back. Certainly it's easier to make the mistakes that beginners make while you are young, but after a few months that won't make much difference.
As for getting out of a rut or reinvigorating your mind, our training has done that for quite a few people, some more than once. The only way to know for sure is to give it a try. There are several options for getting started that can be found on our website. You can click on this link:
http://www.stlki.org/train_now.shtml