I just noticed a striking fact, our dear lad Pippin and Rowanna are of nearly same age
That's true, isn't it? She's a couple of years older than he is. Yet interestingly, even though people of Dunedain descent are generally at least as long-lived as hobbits, I never think of Rowanna as in any sense a "tween" though that's definitely where Pippin is.
Perhaps that's as much a reflection of her upbringing - losing her father at a very early age, living independently with her mother, then developing her own livelihood as a horse-breeder - as of her calendar age.
I certainly tried quite hard, when writing the chapters in Minas Tirith where Rowanna and Pippin interact a lot, to make sure she wasn't patronising him. They're good friends; I think she feels older than him, and she tries to encourage and comfort him where necessary, but actually that's fairly mutual...
You're romping through the chapters, anyway! See - I told you you'd be caught up in no time!