New faces are a great thing. I love the enthusiasm.
Its the older, experienced players who do things like roll their eyes at someone else's character, or call a plotline cheesy, or try to play a personal metagame against the dungeon master, or ruin the mood by constantly signaling that they're too cool to enjoy the things the other players are finding fascinating, or have presuppositions that only particular fantasy archetypes are acceptable in D&D and anything influenced by popular culture is beneath them, or... well, I could go on for a while. Older, experienced players with the wrong attitude are a plague on the hobby and I hate them with the burning fires of a thousand suns that are, themselves, also on fire.
Bring on the new players. Their energy and clumsy enthusiasm is worth a million times more than jaded proficiency.