I Love Pretending To Be Extremely Pregnant

Ok, so I didn't tell my sister that I pretend I'm pregnant because I didn't want to build up anymore stress on to her... right now i'm home alone for three days until my parents come home from bringing my sister to college (I didn't go because I didn't wNt to miss the first day of school) and my grandma is coming over at around 4:45 pm and I'm kind of itching towards telling her and I don't know how. Should I just keep my belly on until she comes over and not take it off when she arrives or have it off when she comes over, tell her then show her?