I think it is fine - I often tweak monsters to fit the level of the party. Either to make a fun encounter or to fit the theme in the campaign.
Maybe not a dragon - but even then you can always throw an "injured" one for the party to fight. Because why not have a early party fight a creature that is in the game name.
Not every high CR enemy needs to be a BBEG for the party, sometimes you just want to give them a cool fight.
