You mean Weaner rats? MY MD is about 1M long (but she's almost 10 months old, not 2 years, lol) and it's what I feed her for the moment. I don't see any harm in doing it. If she can't handle that size she wont take them - simple as that.
Also, I like to monitor how often my Pythons shed to determine if I'm feeding them too much or not enough. For example - my 9 month old Jungle had about 3 weeks between sheds so I didn't increase the food size and wont until the sheds are 4- 6 weeks between each otherr.