v-brakes work but can be a little bit of an issue in the wet.
i would still recommend going to the track on a race
day, paying the $25 and just giving it a go. if you like
it then it might be time to start looking/saving/window shopping
at new XC bikes to up grade to.
i wouldn't at first be too concerned about the length of your frame.
just first see if you like riding/racing. then move on from there.
my first racing bike was a very low level scott. it worked
fine for me and served its purpose of an entry level bike
to encourage me to upgrade.
the track is
here. it is a bit of a labyrinth so best bet
is to just go down and start riding down the first single track you find.
or possibly follow others who are down there. most weekends you
will find a few people riding around. there are lots of
combinations/paths through the reserve.