Depends how big that 1 year old is, in a lot of cases most people tend to be very conservative when feeding (not big enough and not often enough), and while a 1 year old with proper feeding can be anywhere from 60 to 100+ grams many keepers have 1 year olds barely weighing at 15/20 grams.

As far as feeding goes it's not hard just eyeball it, the prey should be 1 to 1.5 times the girth size of your snake, 2 to 3 times a week.