It does seem like today that most of the actors and actresses are starting out younger and younger each year. That is not uncommon to see actors and actresses and you are now in their twenties and thirties and they have been acting from as their whole life.
Some people think that there's a certain age where you can't start your dreams but that is not true. You should never give up on your dreams even if it is to become a Hollywood actor or actress. In movies there always times when an older actor or actress needs to play an older character. Therefore, even if you are 50 or 60, you can still become an actress and achieve your Hollywood dream.