The CRF150F would be a great bike to ride for the first time, but it is a bit on the small side for you. I would expect that you would have a hard time standing on the pegs.
I recommend that you head down to a bike shop and throw your leg over a few bikes. Stay with the major brands (Yamaha, Honda, Kawasaki, Suzuki) and away from the cheap off brand bikes. Just by sitting on a few you will get an idea of what the correct size is. Oh, and pay attention to all the letters in the model names, there is a big difference between a CRF150F and a CRF150R
The Yamaha TT-R125L , Honda CRF150F, and Kawasaki KLX140L all have a seat height of 32 inches. I would expect that you would be able to straddle those bikes with both feet flat on the ground and not touch the seat. That isn't what you want. Ideally you would be able to sit on the seat and have both feet somewhat on the ground.
A Yamaha TT-R230 or Honda CRF230F have seat heights of 34 inches, which would be better for your height. If the bike is too small then your legs are bent too much while sitting which makes it harder to stand up through the whoops. It also means you have to bend over too far to reach the handlebars, which will be hard on your back and legs as well as make the center of gravity on the bike too high.
All the bikes mentioned are four stroke bikes, which are much easier to learn on than a two stroke. They are "trail" bikes and will be a lot more forgiving than an all out race bike.
Make sure that you get the proper riding gear as well. Helmet and goggles are an absolute must, as is a decent pair of boots. Don't even think of riding without at least that much.
Gloves, knee/shin guards and a chest protector are highly recommended. If you are following another bike down the trail you WILL have rocks thrown at you, and the chest protector (also referred to as roost protector) will save you from a lot of hurting. The knee pads will protect your legs from getting whipped by a tree branch. Your hands are always in harms way, so keep gloves on them.
As Gomer said, tell us where you live and what type of riding will you be doing? Better yet, fill out the "sticky" that was at the top of this forum so we can better advise you.
Rod