Pushy friend : Pushy horse : Part 1

I have a friend I have known all her life. This friend is pushy. She tends to say one thing, expect another. She doesn't leave off something once its in her mind.
I have trouble dealing with it, because I see black and white, and no grey in things. She 'LOVES' horses, yet makes to attempt to learn about them. This annoys me, as she is always trying to correct me, without knowing what she's talking about.  
I found myself comparing her to a horse. If I had a pushy horse, I wouldn't let it walk all over me, I'd push back to establish who is boss. So why do I let this friend walk all over me?
Being senior to her, more mature than her and in charge of looking after her, why am I not the one in charge?
When you own/lease a horse, the horse looks to you as the senior counterpart to look after and lead the 'herd'. While the horse may try to push you around, you will always be quick to push back.
So maybe it's time I took charge of my 'herd' and pushed back.
Have a good day!
WildHorse
P.S I am pretty sure that Monty Roberts does some stuff on taking horse behavior and showing how it can be like humans.
A 'pushy' horse (below). 'Pushy' Does not mean the horse pushes on you ;)