Just beginning first national rise (7)
I believe the answer is:
nascent
'just beginning' is the definition.
(I've seen this before)
'first national rise' is the wordplay.
'first national' becomes 'n' (1st letter of 'national').
'rise' becomes 'ascent' (synonyms).
'n'+'ascent'='NASCENT'
(Other definitions for nascent that I've seen before include "being coined" , "Developing" , "starting to happen" , "in early stages" , "Emerging, in the process of being born" .)