What would a normal height range for a filly to be at 5 months if the sire is 15 and the mare is 14th? The filly is 13 hands now and it just seems huge. I didn't think she would grow over winter, but we are still dealing with fall weather up here in the Ottawa Valley and she is still growing...

That is not an unusual height for our foals from the taller stock - there are also many variables that have to be considered. I have seen horses race to a height that looks very promising only to stop growing younger than some of our other lines, different lines mature at different rates. You are best to use one of the measuring guestimates that horsepersons are fond of - measure the cannon (middle of knee to coronary band) if it is 14.5 inches long then the horse should mature to 14.2hh there is another one that is pretty common but I forget the formula...
Ques

From which lines are the taller pasos? She is Coral Lace great granddaughter, Favorite que tall granddaughter and is triple Guamani several gens back on her dam’s side. Are her bloodlines tall?

Sorry, I meant taller of my herd...While I am familiar with Coral and Favorite lines I don’t have them in my program so can’t speak about size produced. In my lines, my taller horses are from the Anfitrion, Regalo Sublime, Bold Star and believe it or not Capuchino horses - now my Capuchino grand babies could attribute their height from the dam's side of my Capuchino son's pedigree....A mare that was imported from Colombia who has good size in her pedigree. I do find that size very seldom comes from parentage further back than 3rd generation.