Great attitude!! :cool:
The bigger the bike, the easier it handles the rocks and obstacles but, if you can't reach the ground to keep from tipping over easily then you tip over!
My son has this dilemma. At 9 YO, he's a bit big for his KX60 but still too short on his CR80E to handle the slow technical stuff. He's been riding this stuff since he started riding 4 years ago but it was a long learning process and I got one heck of a workout during that time.
The two scenarios over the same rocky rooted hillclimbing and descending trails:
KX60 he bounces off of everything and has to stop and get back on track quite often BUT, he rarely actually falls off the bike or tips over.
CR80E much smoother ride except when he gets off track, over they go.
My suggestion is to find the biggest bike (height wise) that you can still touch fairly easily. You don't need to touch flatfooted, I can't touch flatfooted on my CR but I can touch my toes, to the balls of my feet while sitting on the seat.
The Yamaha is probably pretty heavy compared to the newer bikes but, if it is what you have then you CAN learn to ride it. You may want to practice picking it up or keep the hubby around to help you.
I know when I first started riding 3 years ago, my biggest problem was getting my bike upright on my own (KLX300 then). I have pretty well mastered picking mine up from most any position. That does involve the occasional pick it up & flop it over to a better position move but that's what barkbusters and spare levers & perches are for.
The thread FC22 mentioned has some good ideas on the newer bikes.
http://dirtrider.net/forums3/showthread.php?threadid=27808