No. I know of a YC startup co-founded by a person (a friend of mine) in their 50s in the past few years. In the past there have been some who are older than tha

No. I know of a YC startup co-founded by a person (a friend of mine) in their 50s in the past few years. In the past there have been some who are older than that. There are plenty in their 30s and 40s. Most startups are founded by people in their 20s because that's the stage of life when people generally have fewer constraints/obligations (particularly on time/attention, finances). Later in life, people have families, mortgages, other obligations and preferences that make it harder to go "all in" on a startup, the way co-founders and investors expect you to. But YC still funds plenty of older founders who are willing and able to make that choice. There are some advantages to being older; e.g., more experience, established networks.