Not sure exactly what you are saying: Will the backsplash end at the bottom of the window trim? If so, and if you aren't going to show photos of the granite or cabinets, or explain the style you are going for, I'd say no to any trim. Pebble can go many ways, from rustic to...

I know you didn't ask for opinions on your choice of backsplash, but I'll have to support Sophie Wheeler that this will be so very hard to clean in a kitchen - be sure you love it enough to deal with this. Aside from splatters, I can just see all those little pebble tops gathering dust over time.

Kitchens collect grease over time, even if you don't do much cooking. There is no easy way to wipe these tiles/stones down. As Sophie said, pick something else.

Show the granite, show the kitchen and No to that splash. But do it so you can get some help.

I can't see that not being weird in a kitchen. Sorry. :(

I agree poor choice for backsplash and BTW almost impossible to cut for DIYER.

goodnonnie, I often see photos of kitchens that have 'bad ideas' displayed - you can do a google search and find many such examples, but this doesn't mean it's something one should do. Suggestion: If you love the pebble backsplash (and yes, I understand falling for something!) perhaps you could use it elsewhere? I've seen a gorgeous stacked river rock used at a dry bar... or if you have a hutch you could use it in?

Here are a few examples (not pebble, but you get the idea):

We did an accent wall in black pebble (a bit larger than yours). This photo shows where the rock and the quartz counter meet. No trim piece.

One syllable of backSPLASH clearly didn't register when choosing those pebbles.

The grease, the spaghetti sauce, the gravy, the pasta water...ugh. There is no way to keep that clean.

Our wall isn’t around any cooking activity so it works in our kitchen, but I wouldn’t put it near cooking areas because of the cleaning issue mentioned above.