Levels of swimming

Question
My parents are thinking about signing me up for swim lessons.
I sort of know how to swim, but I learned from friends and on my own.
We aren't very sure what level I should register for, because I'm not very familiar with levels and all that stuff.

Here's what I can do:
I can sort of do freestyle swim underwater
I can kind of float on my back. only sometimes

I really want to learn how to tread

Please help me!
Thank you :)

Answer
Hi Wendy!
That is awesome that you want to learn how to swim!!
You should register as a novice but practice a lot on your own if you can in order to move up more quickly. If your area offers private lessons for a reasonable price I would lean towards that if at all possible just for the beginning. It really depends on how far you want to take your swimming skills, novice will give you basic swim technique and a little work-out, from then on is getting a little more into the competitive swimmer's field.
(by the way I can not float either so do not worry about that :)
and treading is pretty easy it just gets tiring, legs are in a bicycle movement constantly pushing down on the water to keep you afloat and your arms are out stretched with palms down slowly swaying back and forth for a little extra help.
Hope this helps!
-Jessica