Pearl, its been a long time since I have shopped at Ski Barn for bike stuff, but they should have a decent selection of helmets. If you cannot find anything there to fit you, follow the advice of everyone on this thread and get thee to Halter's quickly.
I have a big melon, lots of hair, and I sweat profusely, so I needed a light helmet with a ratchet adjustment and plenty of ventilation. I have a Bell X-Ray and a Bell Phi. The X-Ray is my "trail" helmet - it features a removeable visor (as nearly all MTB helmets do) which I seldom wear, it screws with my vision. I interchange them for riding whenever one is too wet from the day before.
I have had much luck with Bell's customer service as well. They sent me 3 sets of replacement pads, Free, for the inside of my X-Ray after I asked a simple question about how I could buy new ones.
Helmets do not really wear out, but if you crash in one and hit your head, replace it immediately, no questions asked. You cannot tell what kind of microscopic damage you may have done to the interior of the helmet, and you do not want to take chances when it comes to the ole grape. A minor crash here and there could leave you vulnerable to serious brain-case damage should your helmet be structurally compromised.