And nobody has an education, maybe just the imam but his is probably limited too

Did Somalis ever go to school before the 1990s?

There’s no reason why Nomads should be above the artisan class.
Well before the 1990s, the country got an international award for having the highest increase in Literacy, from 5% to a % in the high 70s so yes Somalis did go to school before the 1990s.
The hierarchy in the cities also impacted the farming lands and the pastures, as people had relatives living in those cities, traded with those cities, were members of religious Orders and Brotherhoods originating from those cities, and vice-versa. Though artisans in other parts of the world were usually considered more prestigious, in Somalia, where livestock equalled wealth and status, this was not case.
Another factor was their clan, most artisans did not belong to the major clan families, while most of the nomads did.