I'm wondering if ritual Babalities whenever they get too old/decrepit have anything to do with Edenian's long lifespans.

It was briefly debated here years, n years ago. IIRC one negative was the indignity/danger of being in a baby/child body for a while.

In Outworld, who could you trust to take care of them?

Ka-Tra

I think Kitana has already 10000 years when the originals MK happened. Mileena was created and artificially matured, but as seen in MK9, she has the mind of a little girl. I think her maturing process, and her tarkatan blood flawed her aging, and now she ages more like a tarkatan, wich is more quickly than edenians. That's why she's more mature in MKX.

If I had to guess on how is the edenian life cycle, I think it would be:

born-5000 years Child (that's where MK9 Mileena is)

5000-9000 years Teenager (MKX Mileena)

10000-15000 Young Adult (Kitana)

15000-30000 Adult

Just to add something more, I was thinking how old would be Sindel, since she looks very young in MK11 compared to MK9, I mean she could be Kitana's sister for appearance. If I take the chart made above, I would say she's 30000 years old.

It's canon that the Edenians are descendants from the gods which is why they live for so long.

Good theory. Personally I like to think Mileena would outlive Kitana and that she's only partially Tarkatan since her only Tarkatan trait is her mouth so I don't think Shang used that much Tarkatan essence otherwise she would look very different.

As for Sindel I personally have her in the range of 15k to 25k when she had Kitana.

Where is it confirmed OG Mileena is only 1000 to Kitana's 10,000?

Why the large age gap/wait so long to have a child? Maybe it's Kitana 10,000 - Sindel 10,035.

At the very least Sindel could literally be only 16 years older than Kitana instead of hundreds/thousands without the godlike timescale ratio.

Ka-Tra

Well she was created by Shang Tsung and he himself is about a thousand years old based of his history. So Mileena should be around one thousand or a little younger than that.

Some people think Sindel was in her later years when she had Kitana because in her MK3 bio her hair was already white and the black streak came from her resurrection. So Sindel had to have been older.

Wasn't the original MK2 intro or ending of Kitana that said she was 10000 years old? Sorry if I'm mistaken. But I reaally remember that one of her intros in the recent games, Cassie ask her whats her age, she says it's more than 10000 and Cassie mocks on how old is she.

Like Shadow_17-0 said, I also think Sindel was already very adult when she was mother. But hey, this is just theory, NRS could change things anytime, like in MK11 where she looks like Kitana's sister and she's evil from begginning. Personally, I like her MK9 appearance more.

Overall, if I had to translate the characters into human years, it would be:

Sindel - 50 years

Kitana - 25 years

Mileena - 15-25 years