Actually, The Calling had misprints in the first edition (and ebook), which were changed in later editions. It took place in 9:10 Dragon, so the elf baby would be 19.
See his comments in this thread. (it's the filtered version so you just get the first post and any bioware posts. FYI, to do that if you're not on the main page of the forum looking at the thread title just add "&if=8" without the quotes to the end of the URL)

I suspect the comments from Loghain about how Maric would have shamed Rowan by acknowledging him were either about her memory or, more likely, a fuckup from when Alistair was supposed to be a disillusioned warrior in his early 30s that should have been changed or removed but got overlooked. (they scrapped and rewrote his entire character, but much of the game was done otherwise- it was because the first Alistair tested poorly)

This is his comments on a timeline someone came up with from that thread:

emynii wrote...
9:00 - Start of the Dragon Age
9:02 - Death of Meghren,
9:03 - Maric Crowned King (Age 24)
9:05 - Cailan Born
9:08 - Queen Rowan Dies
9:10 - The Calling (Cailan age 5, Maric age 31)
9:25 - Maric Dissapears (Age 46), Cailan takes throne (Age 20)
9:30 - Modern Dragon Age Game

I'm gun-shy of confirming any timeline at this point, and I don't have my notes from the novel on hand -- but at a glance this doesn't look too far off.