Best thing to do would be to go down and have a chat with the instructor/coach(es)/gym owner. If its a decent place they will welcome newbies and probably do some sort of free trial for you to see if it is something that you would like to persue.
When i first started mma being the new guy was a but daunting, you get your arse kicked more often then not but if you stick at it and are keen to learn then it takes relativly little time to get to a standard at which you can train with those that are far more advanced than youself and make really good training session that are beneficial to you both.

Get stuck in