She has lived for over 200 years. We know this because she was imprisoned for 200 years. In the time BEFORE then while part of Master's harem she most likley harnessed the dark arts. She is the more scientific/academic of the 3 vampires, preferring to harness power. That's why she is a Mage, because she was free to learn magic as an immortal undead. In fact it was this promise of being able to learn what she wants, with no fear of age, time or social expectations that made her accept the Master's "gift" to be a vampire.
Her obsession with having a baby is again linked to both her being undead & her academic desire. She is absolutely bewildered & excited that MC was able to defy the natural laws (further) by getting them pregnant. Also if you are a female who is over 200 years old & you know you cant have a baby that would suck for some women. At some point she may have wanted to be a mother but she had to accept she cant. So when MC makes it true... well she jumps at it. Also shes not alone in wanting to breed, Zsofia is OVERJOYED at the thought she is/could be a mother. It's only Reanna who is against it at first.
If they had a child I would prefer she be some kind of hybrid of all 3 vampires. Perhaps some tragic births leading up to some blood magic where Adaobi creates a baby that is daughter of all 3. I have a concept in mind of anyone wants to read it, could be a fun story arc I think.