Your bike sounds fine. Disc brakes are all the thing now, but you really only NEED them if you ride in consistently wet conditions.

The general philosophy that most folks I know go by is, "it aint the bike it's the rider". Sounds like you have a good set of bike handling skills. For some ideas on mountain bike specific skills, I've got a good list on my website,
http://www.specialtyoutdoors.com/pen...g/ridetips.asp

Probably the biggest difference in getting on the trail is how much more time you spend OUT of the saddle, using your whole body.

Now go have some fun.