definitaly the tranny. if your using your short throw shifter for its intended purpose which is shifting faster and more aggresively it wears out the stock synchros. if 1st is gone other gears will eventually start to follow. i would just swap in a used trans thats the cheapest option which isnt cheap but rebuilding is more expensive unless you know how to do it yourself. i had the same problem in my old car. at 1st it would grind in if i was moving a little then it just stopped going in and i had to start in 2nd. man does that suck.