I agree with what
Lily said--it's easier for people to adopt a nickname taken from the first part of their name than from the last part of their name. However, my cousin's name is
Gabrielle, and she goes by
Elle most of the time. BUT, her mother insisted that everyone call her
Elle since she was very young, maybe even since her birth, so it may be a bit harder for you to begin going by
Elle at this point in your life. I wouldn't say it's impossible, though. You just have to accept that not everyone will call you that, especially people who have known you for a long time as
Danielle.
My name is
Devan, and some family and friends call me
Dev. I've been wanting the usage of the nickname to grow, though, so I make a point of introducing myself to new people as
Dev, or going by
Dev on social networking websites, so that old friends will see I'm going by a shorter name.