The little girl I had when small (3)
I believe the answer is:
dot
'the little girl' is the definition.
(I've seen this before)
'i had when small' is the wordplay.
I cannot really see how this works, but
'had' could be 'd' (in contractions e.g. 'I'd', 'you'd' etc) and 'd' is present in the answer.
The remaining letters 'ot' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for dot that I've seen before include "Long-ago year?" , "A point, small round mark" , "Internet punctuation mark" , "Cotton, say" , "Small round spot" .)