This is a wrong way of looking at it, its not really dependent on age, rather than stage of loss. The idea is the more hair you lose, the loss does indeed seem to slow down by itself. This is why you see some guys lose the first few norwood levels very quicky, but then seem to sit at NW3/4 for sometimes decades, and don't lose again until they start to get into their elderly years.
It is not known why this is, some say that as you age your testosterone/DHT may fall faster than your folical resistance to DHT and it creates a "sweet spot" for a period of time where baldness stops. Others say the more bald you are, the less inflammation there is on the scalp, which helps remaining hair.
Ultimately, everyone is different and cannot be predicted easily.
Hell no. I’m 42 and most of my hair loss occurred starting 36-37.
Your genes determine when your hair loss starts and how fast it progresses. The only way to “stabilize” hair loss is to throw lots of time and money at it, though some in here have had great results with just time and hard work.
Someone told me I was losing hair in my crown just as I turned 30, and I've been slowly diffusing ever since. I'm 38 now and diffused as f*** all over. Will be getting a transplant within the next few years.