First brew? I would just stick to the recipe, and avoid the homebrewer tendency to kick the creativity up a notch. Everybody wants an imperial bourbon barrel-aged coffee lavender pale black session ale that is triple dry-hopped with Citra and hemp seeds, but an American brown is pretty tasty on its own. And it could be that it might not finish too dry, so adding lactose might over-do the sweetness.
But in the end, do what you wish, that's what this hobby is here for!