Oh yes! Success has no time limit or certain age attached to it. Anybody can be successful at anytime, be it at young or old age. There are those that find success at very tender age while we also have those that find theirs at later years of their live.
When it comes to success, there is no specific definition for it. What one might consider to be successful, others might not tag it same name, because there are every areas of human lives that if in any of them one fails, we can't say that that person is successful in that aspect of life. In essence, there are those that are successful in career, but yet fail in marriages. Same with those successful in family, but fail in their health.
So therefore, if we really want to define what success is, it can then be seen as a sum total of life achievement encompassing all aspects, not one piece to the puzzle missing. That is called complete success. Interestingly, complete success can't be achieved like sprint but gradually as it is with marathon.