About 3 or more years ago I was in your position. I would find fabric on a "can't resist" sale or friends would give me their scraps and I had those huge plastic boxes full of fabric and had little idea what was in there. So with the inspiration of the good folks here, I went to the Comic Book store and bought 300 comic book boards, then over to Joann's to buy their storage boxes because they were on sale. The storage boxes are the file style so the boards would stand up straight - they hold the boards and I can see the fabric from the side. Then I went through one bin at a time. Separated the fabric by themes (Christmas, Fall-Halloween, Childrens, floral, etc. and solids by color.) There was some I got rid of because it wouldn't work in a quilt. It turned out I had over 250 Christmas fabrics and 100 Halloween fabrics - so I was back at the Comic book store and Joann's a few more times. It took me a couple days to get it all done (I'm retired, otherwise it would have been a couple of weekends).
My fabric is washed when I bring it home - and I do not iron it until I use it. So when I did the sorting, if I didn't think it was washed I washed it then.
After I knew what I needed I went to Ikea and bought some storage shelves. Since mine fit in a closet I just got the wire ones that were the perfect height and width. So much easier than stacking the bins on top of each other. I kept 2 bigger bins for very large cuts of fabric (5+ yards and flannel) and my UFO's. I have notes on the inside that can be seen on the outside that say what is in the bin.
I am sure you will enjoy it - playing with all the fabric, seeing what you actually have is like finding a new treasure. You may even put together fabrics for your next quilt.