If your grandmother is this old and you go see her before the end of the quarantine, she may only has a few month left. You want to see her? Teach her how to use a video conferencing tool.
I've got some bad news for you: until you have been vaccinated for COVID-19 (early 2021 soonest) or have had it and fully recovered and then waited a bit, it would be a bad idea for you to travel to see an elderly relative. It would be selfish and irresponsible to do that.