Never let age decide whether you should start a business or not. In fact, with age comes experience and with experience comes a greater chance to succeed.
Some of the largest companies were founded by people of age 40+
Sam Walton founded Walmart at 44
Gordon Bowker founded Starbucks at 51
Charles Flint founded IBM at 61
Harland David Sanders founded KFC at 62
These are just a few examples of success stories of founders late in their lives.