1993 Jeep Wrangler difficulty shifting into 1st gear

I just bought an older jeep wrangler, 93 sahara, it runs great and is in very good shape. I have one problem that I cannot over come. I have a problem shifting into 1st and 2nd gear when the car is completly stopped. I just had the slave cylinder replaced in hopes to fix the problem. The people that sold it to me have no problem shifting, I took a ride with them and they seem to be fine. I have been driving stick shift for years and I know I am not crazy. Please someone help! I dont know if it is a problem with the transmission, clutch, or what? I saved to buy this jeep and was so excited! I bought it yesterday and now want nothing to do with it!