For reference, the generally accepted standard for determining age from blood is the Horvath clock [1]. It seems to be accurate and only uses a penalized regression. Keep in mind this represents what your age is in reference to a "healthy" person. For example, a 50-year-old who smokes may have the equivalent practical age of a 60-year-old who doesn't. The Horvath clock is useful for evaluating lifestyle changes and your overall healthspan.

If people want to learn more about how DNA methylation relates to aging, I recommend reading Lifespan by David Sinclair.

[1] https://www.semanticscholar.org/paper/DNA-methylation-aging-...