If you look at many tech startups, you will notice that the age of the founders is closely related to the nature of their business. For instance, YC startups do

If you look at many tech startups, you will notice that the age of the founders is closely related to the nature of their business. For instance, YC startups do mostly web software, so the founders should be young because the barriers of entry aren't that high. After all, a smart kid who spends his teens coding in his spare time will be at his best by the age of 20. On the other hand, I know startups which were founded by guys in their 30s and 40s. Their business areas were chip-design and laser tech for optical networks. The barrier of entry in these fields is huge. To cut a long story short, if you're 35 you may be old by web-app industry standards, but you're still young by semiconductor industry standards. Since you're on HN I suppose you're into software, not hardware, so what I have just written will most likely be irrelevant to you.