Transmission problems

So I have a 2001 subaru legacy that was gifted to me with a destroyed throwout bearing. I replaced all of it except the flywheel cause it was in good condition. I had never drove a manual and learned with this car(I stalled alot getting the hang of it) and I’m pretty comfortable with it now. But the past couple days it hasn’t been going into first gear or so it seems. When I put it in first at a stop the clutch doesn’t have a (sweet spot) It moves but just creeps,shakes alot and is difficult to keep it running. It has been doing it intermittently sometimes going right in and other times it wont. Fluid is good, and master cylinder fluid(Dot 3) is full but brown, I need help figuring this out. I did notice that before this was happening second gear seemed like it moved alot more than usual, so much that the trim came off multiple times going into second. I’ve also noticed the past 2 days the shifter pretty much moves back to neutral after shifting to 2nd or 4th but stays in gear. Is that normal? Did I just happen to notice that cause I was having issues?
Is it possible I wore out the clutch or throwout bearing while learning how to drive it? Or possibly damaged the tranny? I have been riding the clutch alot in first cause it was the hardest for me. Recently I’ve smelt the burning clutch smell a couple of times trying to get it to engage in first, and that never happened before while I was learning.