Tranny problem

[KwikR6]

Hey there everyone...I need help. Some advice would be nice. Ok here we go....The other day I was racing another civic. I was doing alright off the line and then when I was shifting into 3rd my tranny wouldn't go into 3rd and my gears grinded I had to drop the clutch (and the race) in neutral and then try again. It werked. But it's done in a few times since when I'm really revving high. Am I not putting the clutch in far enough, and shifting too fast. Or is my syncro mesh going in my tranny. orrrrrrrrrrrrr what do you think? I can't figure it out. I think it's human error personally, well actually I'm pretty sure like 99.9% sure it's human error. And if it is would a new clutch help or a short shifter. So my gears won't grind when I shift too fast. Bekause I would really like to know how to make the shifts better and smoother and faster. Thanks.