bf going to ask me to marry him

So my boyfriend bought my engagement ring which I helped pick out but I'm leaving it up to him as to when he wants to propose as I should. But he's old fashioned and wants To ask my mom for my hand in marriage. He asked me last night if I want to just be engaged before he meets her though because he's afraid she'll say no and he will honor that. The reason she'll say no is cuz I'm only 20 but it's different because it's military lifestyle and I'm still going to be going to college. What do you guys think? Should I tell him to wait and ask my mom for my hand and see what she says or for him to just ask me?