Congrats on the seed germination.
I am surprised I do not hear about more people germinating citrus seeds, particularly from less common varieties or ones usually seedless. I do it all the time to help grow my citrus collection. I have a couple of Juicy Crunch Tangerine seedlings from seeds I germinated last winter.
That being said, who knows exactly what type of fruit your seeds will produce or when they will start fruiting? As to the latter, I would guess six to eight years. According to what I read about the variety, Orri oranges are hybrids of Temple tangor (or maybe Orah mandarin) and Kinnow mandarin. Those varieties are themselves hybrids. Orris produce no seeds when planted in solid blocks but when planted near other varieties, will produce seeds, probably due to the Kinnow parentage. Its Kinnow parentage might also give it some resistance to HLB. But, whatever it was pollinated with might give it some traits that Orri does not have.
You never can tell; though, your seedlings might turn out to be the greatest tasting, most HLB resistant new citrus varieties ever developed. Or, they will probably just be average, good tasting oranges.