ok let me save you some trouble and give ya some insight on this...
I run a thief guild on atlantic, and many of our members are having the same problem. I have heard that it is a known issue that the npc thief guildmaster is bugged and tells everyone they are too young. SUPPOSEDLY they are working on it, but i know members in my guild who have been trying for the past month to join it. Personally, i think this is some conspiracy to try and kill the rest of us off lol...even if it is, it's not happening.
And to the guy who says you can only steal stacks of bandages and regs...in the past 2 months alone i've stolen:
2 inquis reso
armor of fortune
orni of magician
2 val runic hammers
folded steel reading glasses
mace and shield glasses
kryss worth 20mil
And along with that a bunch of other stuff that slips my mind. And yes they were stolen (not scammed) from players, not from doom, and the arti's are not cursed. Not meaning to brag, it's just that i hate when people jump to conclusions to assume thieves are dead.
P.S. For the record, you can be boosted over 60 steal with jewels/items and still join the npc thief guild. After you join...if you remove the items and go below 60 steal again, you are still in the guild. Also, when joining, make sure you say the guildmaster's name, followed by "join". For example: "Timothy Join".