Telling My Parents I'm Engaged

Gabrielle
So my boyfriend/fiance (I'm 18 and he's 19) and I have been together for over a year and a half (friends for almost 4 years) and we recently moved off to college together. My parents are helicopter parents and his parents are conservative and traditional. He proposed to me and I said yes, but now we have to tell our parents. And I want to, I'm just afraid of their reaction. We agreed to tell them this Christmas, since they'll all be around each other and close by. Advice? Encouragement?