Juventas was the
Roman goddess of youth, not so much of abstract youth or youthful beauty (as Hebe was) as more narrowly of the juvenes, the young men of military conscription age (17) including boys preparing for this, which they did at age fourteen on taking the toga virilis, the garment that proclaimed them to have reached 'manhood'. Latin juvenis (or iuvenis) simply means 'young' (compare English 'juvenile' and French jeune).
