When do you get morning sickness & how bad is it?

Robin
My mom is here June 1-10 and I don't plan on telling her yet. I hit 6 weeks today. We are supposed to be going to my nieces bday party, maybe kayaking and to a music festival so I'm crossing my fingers I don't give anything away. Trying to hold out til mid July when I'll see her again and be around 13wks