Nope! It's stated in MoR that, unlike other advanced spells, the patronus is considered too difficult because of things like precise movements, and the emotional/willpower aspect, not magical strength.

So the gestures were complicated and delicate. That didn't stop you from learning it when you were eleven. It meant you had to be extra careful and practice each part for a lot longer than usual, that was all.

Most Charms that could only be learned by older students were like that because they required more strength of magic than any young student could muster. But the Patronus Charm wasn't like that, it wasn't difficult because it needed too much magic, it was difficult because it took more than mere magic.