Congrats on your graduation and on starting to wear the kilt! My first kilt was a Utilikilt Mocker and it was a comfortable way to start. I always wear a belt with my UK, it's far too loose to wear without one. I have moderately wide (just shy of 2") leather belts (brown and black) that I wear with it. They're the same belts I'd wear with p@nts. I do not ever wear my more "traditional" kilt belt with it.

I can't give advice on kilt shopping in Scotland (I was only there the once and far too briefly), but I'd consider a tartan with a bit of color to it since you already have a black UK. Do you have any Scottish heritage? Check out your own clan's tartans. If not, look at the universal tartans out there. Personally, I have the UK Mocker (olive green), a wool casual from Burnett's & Struth (in muted MacPherson) and two (well, as soon as the post arrives today) PV casual kilts from USAKilts (in MacPherson hunting and the Scottish National tartans). I won't go into endorsing the latter two incredible kiltmakers, but be sure to do your "homework" here on XMTS and use the search feature to read reviews of any company you order from.
Best of luck!