Mythic blood is a Hermetic virtue, I expect it will manifest when his arts are opened.
I do not see a reason to hinder the opening of the arts for magical blood- note that when it does manifest (I'm guessing puberty) it will be as per animal blood for draconic features.
Does 1 points in Order of Hermes Lore, 1 in magic theory and 5 in Latin work from Journey home thread work? Also added the 1 confidence point in.
Its a long boat ride after an intense adventure, so yes.