2002 Jeep Grand Cherokee Transmission

Well it started once the cold came around. I would it it from park and into drive and just that does not work right. It usually takes it a few secs to jerk into the drive. But the worst issue is it struggles to change gears. It revs really high and sometimes still wont switch into second gear. I typically always let my car warm up once I drive it, but does not seem to help. It is usually only the first time it tries to switch through the gears once I start the car but once it goes through all of them does not seem to be so bad. But the first time it goes through them it is just terrible. The biggest gear struggle I think it has is going from first to second. Clearly its a transmission issue. I just don't know exactly whats wrong with it. I keep the tranny fluid filled too. Should I try replacing the fluid? Please get back to me. Thank you for your time