Yes, but up to about 23, you're growing and maturing. You peak then, and after that then you're really just dying slowly.

Also related: our brains slow down as we age so we perceive time as going faster (like for kids, the summer is forever, for old people, the days flash by). So from a human's perspective, for an average lifespan, we perceive half way about at 23. So it you're over 23, from your perspective, you're over half way through your time.