hello sesha ... I now have Garters exclusively but I did have a Ribbon as my first snake. At the time there was little info on Ribbons but some kind soul on this forum guided me. I did get my Ribbon to eat a pink or two for the 2 years I had her but it was an *accidental* feeding as the f/t pink was thawed in fish water w/fish. I was unable to get her to repeat it more then twice in 2 years.
_ instead of goldfish get Rosey Red feeder fish from your local pet store. These are also referred to as Fat Head Minnows. There are no dietary concerns with these. If you can pull off a pink, GREAT, do it ! Personally I would try a SMALL pinky.
_ have not heard of dusting or any other supplements for these animals.
_ sexing is not all that important IMO ... 10" nose to tail I would guess to be a yearling give or take a month or two.
Here's a link/address to the guy who shared alot of info about Ribbons with me years ago ... like 10 years ago
It's a great website.
http://www.mcwetboy.com/reptiles/
best of luck to you !
mt