Buying a youngster....?

it seems to get the quality of horse i want for the money i have i will need to buy a youngster. i have had 6 years experience with horses but i have never brought on a youngster, i have always had older horses. My mum has spent her whole life with horses and has produced many, including ex-racers and the odd stallion here and there so i dont doubt her knowledge and she says she will help, BUT mostly it will be me on my own and i sometimes fear my experience! anyone who has brought on horses? all info appreciated.................