I would save your character description for when you apply to a game.
Many DMs may set out certain requirements for their game, and every game
is different, so those requirements can vary quite a bit. It
wouldn't hurt to download the free basic rules and look it over,
especially skill checks and combat, and spells too if you want to play a
spellcaster. DMs (most of them anyway) invest a lot of energy and
effort into their games, and it doesn't hurt for players to show some
effort as well. When the applicant pool is a faceless mob of, "pick
me!" and, "can I join?" you need to do whatever you can to distinguish
yourself. Don't get too discouraged if it takes a while to find
your first game. DMs can be picky, as the number of players outnumber
those willing to DM. Look for the "Welcomes New Players," tag and read
any instructions carefully. People that cannot follow simple
instructions don't get invited to many games because there are 5 others
behind you that can easily do so. I actually take it as a good sign
when a DM has an application process. It means they've thought about
who they want in their game, and the result is usually a more cohesive
gaming group. As for being new to this, you will find you are not
alone here. There are a lot of new people coming to Roll20 every day.
In a few weeks or months, you can probably be the one showing somebody
else around Roll20, and inviting them to a game! Ask any
experienced DM, and I would be surprised if they say they didn't like a
gaming virgin to join their games once in a while. I could say newbie,
but that doesn't really express it as accurately. :) The good thing is
that newbies don't carry some of the baggage that veteran players do.
They can really surprise the DM...and that's not easy to do if you've
been gaming for 10+, 20+, or 30+ years. [Wow, I just felt a little
older all of a sudden--it was like a disturbance in the force.] Anyway,
don't think of your newbiness as a detriment--it's not. Now get out there and kick some dragon butt! And watch out for those tails!