General opinion? I would recommend you do what you are comfortable with and happy with.
Personal opinion? Take your time, be wary of a dominant who offers anyone a collar when the person offered has no understanding of what it means. Collars can be used as a tool in BDSM and a fashion statement. But collars to many practitioners of BDSM is as important as a wedding ring and it means that you are accepting His control over you - and do you truely believe you are ready to submit all of yourself in that way?
As for castlerealm, its is a good site to look through, but I wouldn't just peruse there. It does have the romance and flowers vibe about it - and if thats your thing - fair enough. But I would strongly urge you to look at numerous sites and not centre on just one. Find one you are comfortable with.
castlerealm leatherandroses informedconsent DeviantsDictionary AkashaWeb(Femdom) LovingDominant Wikipedia BDSM Health Also read if you can.
The Loving Dominant by John Warren, SM 101 by Jay Wiseman, Screw the Roses, Send Me the Thorns: The Romance and Sexual Sorcery of Sadomasochism by Philip Miller, Molly Devon, Different Loving : A Complete Exploration of the World of Sexual Dominance and Submission by by William & Gloria Brame.
All of these books can be ordered through good local booksellers, Amazon or ebay.
Don't feel rushed or pushed or pressured. And above everything else - ENJOY!
Peace and Love