Congratulations for being so healthy (4,3,3)
I believe the answer is:
good for you
This clue might be a double definition.
'congratulations' is the first definition.
(I've seen this before)
'so healthy' is the second definition.
'good for you' can be an answer for 'healthy' (synonyms). I am not certain of the 'so' bit.
'for being' is the link.
Can you help me to learn more?
(Other definitions for good for you that I've seen before include "Generally, fruit and veg is" , "wholesome" , "Vegetables are meant to be" , "Well done! Health-giving" , "Very fatty steak may not be" .)