Attolia's Age Theory
I can't work out Attolia's age exactly, but I can post my working here. It might be useful when we get more information in future books. Thanks to
immortalbookwrm for patient listening and adding her own ideas for 2).
1) Based on the quote: "He needed a nursery, not a bride, Attolia thought bitterly, though she herself had been engaged and married even younger."
I've already worked out that Gen is 18 at the end of QoA when Attolia makes this observation. Attolia becomes queen and gets married in the same year.
x=Attolia's marriage age/age she became queen.
y=Attolia's age at the end of QoA
x<18 because Attolia was married younger than Gen is in QoA (see quote). Thus the maximum age Attolia became queen at is 17 years.
y=7 years+a few years Attolia has ruled more than Eddis+x
y>7+x
Gen is 15 in The Thief so I'm guessing, that is the coming of age time, if not younger. Assuming Attolia got engaged at 15 to be married at 16, her age would be at least 24 years old in QoA because she has ruled at least 8 years, probably a few more. So their age difference is 6 years. It fits because, as Tal pointed out, Eddis is implied to be a few years older than Gen and a few years younger than Attolia. (Attolia was sent away to live with her fiance's family for the year up to her marriage.)
2) Cute scene: Gen is older than 6 when he watches Attolia dance from the orange trees. Thus 7 is the youngest he can be. This would make Attolia at least 13 at that time. However, Attolia can be no older than 14-15, her engagement age, making Gen more likely to be 8-9 years old.