My 112th birthday is a few years off, so it's hard to guess what the world will be like then or more pertinently what the medical skills will be like then. Life expectancy has increased dramatically over the last century thanks to advances in medical science, so 112 might seem like a normal age to be when I am approaching it.
Having said that, I think it would depend enormously not on health so much but on whether I still had lots of friends and family living. I know some old folks who have ended up the last of their generation to be alive and have been quite ready to die.
I cannot say now however I am sure I would not want to be even 100 -at this stage, way below that age, I do not think I would make it anyway, but if I did I would surely be in bad shape and not want to be around.
Oh yes - but only if I was still 'with it'. Would not like to be alive only to be a drooling mess in a bed. I would jump at the chance of immortality, if I could get it! Where is a vampire when you need one! :)