Haven't reached a dragon yet but it would be insane dumb if u went against a red dragon (the strongest of chromatic dragons) at level 4. Or even at level 10
LOL.. might want to check your monster manual. Red Dragons come in CR4 (medium) and 10 (larg) varieties. Meaning they are a speedbump encounter for a party of that level, and easily handled below that with some prep. D&D has always been like this. Check out the low HP on a 1st edition dragon then imagine it getting wailed on by a fighter for 3d6+strength+magic+specialization at 2+ attacks per round and tell me they are "end game". DragonS (plural) are mid to endgame.