I've known many, many women and girls with this name (both older than me and younger than me) so it does seem dated and just not very special to me at the moment. OTOH,
Susanna or
Suzanne would feel fresher at this point. Having said that, I feel if you love
Susan enough, then use it. Oh, and I agree that
Susie is darling.
"Darkness cannot drive out darkness; only light can do that. Hate cannot drive out hate; only love can do that." --
Martin Luther King, Jr.