https://www.houzz.com/magazine/how-to-get-your-pendant-light-right-stsetivw-vs~251166-to-Get-the-Pendant-Light-Right
I found this quite expansive in helping you to get the right height. I, too, had a kitchen with 7' ceilings, but my kitchen itself was very small as well, so I chose a flushmount. I hope this helps as the size of the room, the amount of light, both natural and illuminated, what you want to use the light for, task lighting, mood lighting, etc. will all come into play. But, I say hold it up there or tack it and look at it for a few days to see what looks and feels correct and you will come out the best. One hint, leave extra wire in the wall in case the next homeowner might like it longer or maybe you will in the future, who knows?

Yes, 28-30 above the tabletop is generally pretty good.