I think the more you expose yourself generally (I mean as a seller) it doesnt really matter if you auction or have your own site.Â
Just by posting here, perhaps joining panty trust too is already a really good step to get noticed.
I have never run auctions (apart from on my own site) but I would think that is a good start to get noticed when you are new, and then build a site at your own leisure.
Your Panty Trust page could be your main personal page until you can get a proper website up and running of your own.
As for competition, don’t worry about other sellers, just concentrate on you. Just do it B)