You turn to the page that claims that you may regress anyone you chose, including yourself. Being that you loved your childhood, you would regress yourself and since you are 20 years old you dont want to remove that many years. It could be fun but the idea of what would happen if you were too young to talk...in other words not be able to recite the spells. But at the same time dont need to relive ackward puberty ages.
You re-read the page over and over to make sure there arent any tricks. But spell looks very basic.
"I. Spell One: Age Reversal
In order to age one in reverse you must select your target by pointing at them. If you do not point at a target, you will be the target of your own spell. To activate this spell, speak the command workd "Regress" and think clearly how many years you want the client to be regressed. It it possibly to regress one as far as a newborn, but you can not unbirth one with this spell alone. This spell consumes only a mild amount of energy."
Since you are not regressing anyone besides yourself, you know you dont need to point to anything. You say the magic word "regress" and quickly think of the amount of year you want to regress