Bed sized quilts are harder to make than lap size. As a beginner I recommend doing a few small quilts first before tackling a bed size.
If it dosnt turn out nice your not out the price it cost for a large quilt.
I also reccomend getting a Quilt In A Day book. Eleanor Burns makes quilting easier and her instructions are very detailed even to which way to iron your seams.
Be sure to watch lots of videos, there are many free ones on the web.
http://quilterstv.com
http://quiltinaday.com
Lots of free videos.
This board has lots of good advice also so have fun learning.