I have a 1996 Honda Accord Coupe with a 2000 VTEC Engine installed...the transmission recently started screwing up...it works fine up until 3rd gear but will not shift into 4th gear. After about 24 hours of not driving it and the car resting, I can start the car up and it will shift into 4th gear but after that it wont. Is this a speed sensor problem? Or does the transmission need to be replaced? Nothing is wrong electronically to my knowledge, at least nothing is showing on the dash that there is.

NOTE: I am a girl, so everytime I go to a mechanic they tell me it needs all of this and that and I really dont want to get scammed. So any guidance is appreciated!

Thanks!!