Hitting milestones is great, and if you keep celebrating, you can do it again and again. I say that because I start slow every year, and assume everybody who doesn't have a trainer has to do the same. So look forward to 30 and more, but celebrate 20.
I remember my first bike ride in 12 years when I was 28 (a while ago). Hills. 2 miles. I literally (and I know what 'literally' means) had to crawl upstairs when I came back. A few weeks later, I was riding to campus in less time than I could drive, park, and walk to my destination. And I start every year with 2, 3, 4, 5, 7, 10 mile rides just to break in my butt.
Numbness is unacceptable. There are now lots of good solutions to numbness, but no single saddle/seat solves it for every on. I'm 220 and 5' 7", and I like the Selle SMP Trk - under $60 at Amazon; I've ridden it over 1000 miles with no numbness.
ISM (ismseat.com) also has a good solution, and others swear by Specialized, especially Power, Brooks B17 & Cambium (with and without slits), and Selle Anatomica. Pick one and stay with it if it works.
The thing tha keeps me away from Selle Anatomica is that someplace they say the weight limit is 450 lbs. I usually get my butt off the seat when riding over RR tracks and other road irregularities, but I fear that if I don't, the force could go past the limit.
Maybe someone who understands the physics can enlighten me....