It is kinda risky for you noth because that is the money of your grandma and that is not yours and whats gonna happen if that money will lose what happen to your grandma she will blame you because of that thing just make sure that you will have a lot of patience because bitcoins are gonna be a long term investment and make sure you have the guts to wait for that because you will cause you own grandma a bad thing she doesn't have any work and you took her money just for your personal want