For a lot of people a convention can be a bit overwhelming. The pictures, the attitude, the atmosphere it can be a bit much for a lot of people. If you find a con with a subject you con support then by all means go for it. Here are some things to know to make your time there much more enjoyable.
First, is plan what you need (food, room and board, spending money, etc.) When you go to a con most times the hotel will not allow many secondary food vendors in. So unless you want to go for a walk, and often times they will set up not so far away form the con so it will not be a long one. Then you will need to have some way of eating because the worse case scenario is you not being at your best to enjoy the good times to be had. You will also be surprised how many calories you can burn in such settings.
Pick out a couple things you want to go to and leave the rest up to your whims. Over planning can really drain you and although you really to get all the place can offer there is a charm about just milling about seeing what your fellow con attenders can get going.
Get social, bring a camera or at least a notepad so you can keep in contact with your new friends as time goes by. To help with this please keep yourself springtime fresh. Conventions do have a bad stigma attached of a couple people per con being what you called fairly ripe. for those who are not educated on the term it means they reek like a seat cushion after chili night.
Last is make sure you have funds to get a couple items. A little spending money may be all you need if you have a mind to haggle. Go out to a con and have some fun.