It is important to keep your brand focused but be open to change.
As you grow as an artist, your brand will need to be adjusted. Also, your brand and type will change as you get older. The girl next door can turn into a soccer mom, the brilliant nerd can turn into a wolf of wall street, punk rocker can turn into motorcycle gang leader, and so on.
Any changes you plan on making, keep your brand in mind. Big lifestyle changes that can alter your brand include visible tattoos, drastic hair cuts or color changes, visible piercings, or wardrobe changes.
A piece of the puzzle that formulates your brand is how people perceive you. Any lifestyle changes should be heavily considered because how you think it may look may not be how the audience perceives it.
On the other hand, if your brand would need a drastic lifestyle change, you should have an open mind to the change or consider changing your brand.
Make sure whatever you decide, you will be able to publicly live with this brand and develop it as you become older and change as an artist.
Do not pigeon hole yourself into something that only has one age range and can not grow.