Mae govannen, welcome to Planet Tolkien, Ashwyn! I wish you a long and happy stay here. It all may seem a little daunting at first, but here's a mini-guide to get you started:
• There are different types of forum for different subjects. The one you posted on is for greeting newcomers, as you found out, but there are also ones for discussing the books/movies, the website in general, polls, Tolkien-related trivia, games, posting your own stories and poems (as you seem to be good at), and many other things that I can't think of at the moment. You can even create your own character and journey through Middle-Earth with other members in a Role-Playing Game (RPG). Drop in at the Khazad-Dumish Inn, or go on a more dangerous adventure in A Dark Threat from the North or Eruheran's Quest, the three active RPGs at the moment.
•Editing your account: You can change different features of your PT account through 'My Account' (top left on menu bar). You can upload an avatar (picture when you post, must be 70 by 70 pixels and must be in .gif format), change your personal info, view updates on PT, and send Private Messages (PMs) to other members if you want to alert them about something. However, it does cost mithril (20 pieces of which you get when you login each day). It depends where this member lives in PT (I, for example, live in Osgiliath, and you in Lothlorien, so it'll cost something along the lines of 5 pieces to send). It costs 400 mithril to change your location.
•Under some members' avatars you may see a little black box with 'Council Member' written on it in white letters. They are a part of the Council for being old and distinguished PT members (hope I didn't just offend anyone - hee hee) and have administrative powers, meaning they can edit other people's posts if they go against website rules (we are a Family Friendly website, so no swearing or profanity please).
Phew! Hope I've covered all the important stuff. To finish, I'll quote Grondmaster (a.k.a Grondy, Council Member, something in the region of 25'000 posts under his belt, off sick at the moment) and say: Share and Enjoy!