>>I am getting ready to purchase my first crested. I have everything all set up. I was wondering however is it better to get them young (4 months old) so that they get used to handling or can an adult also get used to handling? I saw an adult that I just loved the coloring of.
If your object is to have a gecko that tolerates handling well, it is probably better to start with a juvenile, as it won't have a lifetime of being used to not being handled to unlearn. That being said, adults are, generally speaking, calmer, so expect juveniles to start out pretty nervous/jumpy and gradually get more used to you. A good technique in general is to just put your hand in the enclosure near them, be patient (try not to chase them too much), and let their curiosity get the better of them. This may take quite a while, so significant patience is required, but think about how you'd feel if something that was several hundred times your size/weight wanted to pick you up! I doubt you'd be calm about it at first, either! Eventually, with enough nonthreatening contact, they'll calm down.
-----
0.1 Albino Leopard Gecko - Tigger
0.1 Crested Gecko - Pooh-Bear