Yes, on City Hall or an in-game computer, not Town but NRaas > MC > Sim > Intermediate > Age Relative > (filter to the sims you want to age adjust or "X" to dismiss the filter and select All or those you want by name) > 80. Or maybe the prompt and 80 entry come before the filter, am not in game at the moment, but it's something like that.
But if a fair number or all of these sims are subsequently going to be shoved into an older life stage or be placed at the final day of their current stage, I wouldn't recommend doing that on an entire world in one go. The number of now "late" or ready to age up sims all at once might be a bit much for Overwatch and the game to process one at a time. Or it might be just fine, depends on the population of the world and how busy the game engine is doing other things at the same time.
