You have two questions. Do I believe there is life beyond Earth.
Do I think we will encounter it within “this” lifetime.
Who are you talking about, me or you? I’m 64 years old.
Not within my lifetime, anyway. Maybe within yours, but I doubt it. It is more likely a few hundred years from now if any life exists at all in our solar system besides here on Earth.
Any extraterrestrial life that we do encounter within our lifetimes will either be single cell bacteria or simple multi-celled micro-organisms. We would discover those life forms on the moons of Jupiter or Saturn like Titan or Europa. To get there we will have to send a probe and remotely borrow a mile or two through solid ice. Then they would have to release a robotic submarine snoop around. That submarine would then have to have a way to transmit findings of life, if any, back to an orbiting receiver, which would relay that back to Earth. Just getting all that hardware way out there for that endeavor would take more funding then anyone will want to consider, if it even if such hardware existed.
We are not likely to have that technology within our lifetimes. Two, three hundred years, maybe.