I say "go for it"

Its an amazing opportunity and just meeting him doesn't men that you have to continue the relationship. I met my father after many years of not seeing him (many years ago) and while my brother was interested and wanted to talk, I was disgusted by what he had to say and left. The wonderful thing is that you are now an adult and you can decide if your grandfather should be in your life or not!

Do it. I wouldn't want to say no and then wonder for the rest of my life if I should have said yes.