First to welcome new girl, e.g., making us squirm (7)
I believe the answer is:
wriggle
'squirm' is the definition.
(synonyms)
'first to welcome new girl e g' is the wordplay.
'first to' indicates taking the first letters.
'new' indicates anagramming the letters.
The initial letter of 'welcome' is 'w'.
'girl'+'e'+'g'='girleg'
'girleg' anagrammed gives 'riggle'.
'w'+'riggle'='WRIGGLE'
'making us' is the link.
(Other definitions for wriggle that I've seen before include "Squirm" , "Move like worm" , "Move with short twisting jerks" , "Move writhingly" , "Twist to and fro" .)