Welcome, Carola... admitting it is the first step to curing an addiction...LOL... unless you don't want to be cured... just like me!!!
I think I would go through your files and delete what you think you will never use. I have had to do that a few times! I usually download as kits and keep them in kits, calling the file the name of the kit. The designers are pretty good at labelling their work these days, so it is pretty easy, in my opinion, to do this. I find I use a kit more if it's all together because usually all the pieces in the kit co-ordinate, and I'm all about co-ordination. Anyways, I babble...lol... I hope that helps, and I am really looking forward to seeing some of your work, and be sure to join in the challenges we have here!!! Lots of fun!!!