Hello and congrats!
What brands are you looking at? We just bought our first after many months of research. We bought a used (1999) Starcraft Galaxy. My recommendation would be to look for a newer used pop up. You save thousands of $$ and have tons of amenities. We found many from 199 to 2001 that people used just a few times and traded for a larger one or a hardside trailer. Another good thing to look for is plenty of storage space and accessability to the fridge when its' popped down.
For less than $4750 we have a 12 ft, sleeps 8, 3 way refrigerator, heater, bunkend fans, upgraded stove, storage drawers in our cabnets, add-a-room, awning, and skirting around our unit. It also came with scissor jacks, leveler platforms, bubble levels, double lp gas tanks with cover, spare with cover, and a cover for storage. We didn't look for one with a potty or shower because we always camp where there are nice facilities.
Have fun looking and make sure you check the quality!