Can I do it, right here, right now? No!
Do I think it possible? Yes.
I have known beyond any shadow of reasonable doubt that indefinite biological life extension was possible since 1974, but not how to do it.
Lots of people are now working on the details of the problem.
It is very complex.
Some interesting first approximations in this article:
First hint that body’s ‘biological age’ can be reversed
though I hate the title, as it has been obviously possible to me for 45 years, and for some others I suspect for much longer.
My best guess is that reliable and safer than the alternative technologies will be generally available by the mid 2030s (and that involves a number of intersections of very complex systems).