The Hebrew doesn't SAY they were 24hr days. Reading English meaning onto ancient Hebrew is to ignore the data.
Sorry, but those who wish to read it as "age" are the ones who ignore the data.
Of some 2200 usages of "day" in scripture, some 1800 of them refer to a regular old day(s). Most of the remainder are some derivation of "day."
Roughly 8 usages of those 2200+ have to do with "age."
The nature of the story being told in Genesis 1 does not suggest other than a normal day.....evening & morning were day one...two...three....etc.
I understand from some other post that you might be some variety of theistic evolutionist. Is that correct?