Hope you're out having fun!
I rode trails for a bit, and then when I THOUGHT I was fast I started to hit the mx tracks... A few years later and I'm still "slow". I can dust up pretty much all the guys I learned to ride with now, but my racer buddies usually give me a good challenge!
Don't worry about the height of the bike, I'm 5'7" and it doesn't bother me any more... Except the other day I went over the bars in a cambered corner at gopher dunes (easy to go over the bars in the deep sand in a corner if you blow a berm). kept the hand on the clutch to keep the bike running, but was on the right hand side of the bike and the camber was too much for me to get my leg over the bike so I had to push it to a flatter spot. Glad I wasn't in a race! Was actually having a good day, kept up to guys I used to have a hard time keeping pace with.
We should organize a group ride day at Gopher dunes so we can hit the track and trails. They will likely be open in to November if the weather stays this way... I shouldn't be riding more this year since I'm pretty sure I slightly tore my meniscus on the weekend, but I'll just finish this season up and hope I heal up in the couple weeks until sled season!