Those IVs are good. The starters have kinda middling CP anyway so they're more useful as attackers in my opinion.
If you don't need them as attackers then you can hold off if you want more XP later on.
If you don't have the third stage evolution in your Pokedex then that's 500 extra XP during double XP, or 1500 if you have a lucky egg on top (2000 XP vs regular 500).
If that's a big deal for you, then hold off on evolving.