Another question: will you influence how it's spent??
If I had come into $3,000 at age 18 I probably would have spent it on lifestyle while in university (probably would have drank most of it). I would hate to see that savings just get squandered. So would you/will you try to be sure it's used responsibly??
Well, its technically my DS money now. He has full access to his accounts. They are custodial accounts because he is a minor but with the debit cards, online access and whatnot, he can get 'his money', and do as he pleases. Yes he is 12 years old. He technically can order from amazon, or any other place he so wishes, he can go a store and buy what he likes right now. I don't keep track of his bank card. That is his responsibility. He can to an ATM and get cash if he so wishes. So 'coming into money' at age 18 isn't a concern. The child I have is focused on Math and Science and wants to go to University for a career. Thats not to say at some point a social life wont become important but he understands consequences at this point.
As for influencing how the money is spent. Nope, DS has his money. No one gets to influence how I spend my money. I grew up in a very controlling house, and money was controlled. If DS wants to buy something, or blow his entire balance than he can learn from that experience. Better to learn at age 12 or 18 than at 30 or 45 .