That's not the point... Why you even went with the hair? The age pretty much makes it impossible for Blast to be Saitama. Blast in Tatsumaki's flashback looks like an adult while Tatsumaki is a kid... And Tatsumaki is older than Saitama. Those "time-travel" theories are such horseshit... I'm astonished at how some people actually like this type of thing or want it to happen.