Honestly I don't know. Pros would be I could experience all the world has and will offer. Cons, are id outlive all my friends. If I took it now, id be a teenager forever, and that would severely restrict me unless I can still count years. But if this fountain just gave me the power to live forever, I wouldn't be immortal and would still be able to die from an accident or something.
I dont know what I would do if I had the choice, id probably do it and regret it afterwards