If you haven’t decided if you want to be a singer yet, turn back now because A&R coordinates aren’t looking for anyone who isn’t sure of themselves. They are looking for someone that can stand within the spotlight for a long time. Typically, young artists are more marketable as they can keep and grow their fan base as they age. This doesn’t mean that older artists have no hope, as another method is knowing your USP or unique selling point. Not only does this separate you from the rest of the crowd, but it shows that you have a mind for business as well as a marketable talent and how serious you are to make this work.
Although being older superficially hurts your chances, it also increases the likelihood that you’ll have things that will hold you back from being completely immersed in your music. Typically, those who have spouses, children, or substantial domestic responsibility are rejected as they won’t be able to handle the traveling that goes along with the business.
This is if you're thinking of being a singer in the record label sense and touring (which is why this article is mentioning A&R's in the first place!)