Congratulations on your weight loss - the loss you have already attained is no small thing and, ime, puts you well within the limits that barns that have limits usually set (200 is what I have heard from others- none of the places I have personally had contact with have ever even expressed a limit).
As someone who also struggles with weight, I can tell you that, in general, the self conciousness never stops - regardless of what weight you attain or how much you gain/lose. The number on the scale doesn't really have much to do with it. I finally just had to bite the bullet and just get on with it, getting back in the saddle is what gave me that confidence that a number on a scale never could.
Plateaus in weight loss are a common issue/struggle. I, personally, would not let 10 pounds stand between me and being back in the saddle. I would call around and visit some barns just to get a feel for what the atmosphere is in various places to find one that feels welcoming to you.