I think a crested is a great choice for first reptile. They are about as easy as it gets, and are very chill pets. Blue tongue skink or uromastyx are also good suggestions, but are more demanding in terms of the enclosure than a crested. I think a 18x24 would be about minimum for a crestie for life.
Good advice given so far, If I were you I would watch a bunch of youtube videos or read reptile specific pages though instead of just asking Q's on a fish forum. Tiki's geckos has a ton of videos.
One thing to consider is a bioactive vivarium, it is basically a living ecosystem where the plants use the gecko poop as fertilizer, and isopods/springtails clean the rest of it. if you don't have bioactive enclosure, it is important to clean the tank about once a week (go in and remove turds, wipe poop from walls etc) or it will start to stink.
Here's a thread I made on my bioactive enclosure for my gargoyle gecko (relative of the crestie).
https://www.monsterfishkeepers.com/...-vivarium-gargoyle-gecko.731615/#post-8251390
I have since sold this enclosure and built a bigger one that isn't bioactive, so now I have to go in and clean it out. Either way it's pretty easy to keep rhacodactylis geckos.