I'll stay out of the debate because I am wicked.
Like Paints said, I have an extremely low bullsh!t tolerance.
That being said, I have just a few words to offer the OP.
If you think you will be able to sell this foal at anything but a complete loss of the money you put in, wake up. It's simply not true.
If you are breeding your mare because you want to ride a slightly larger pony - buy one. You will spend far less money in the end, and you will have a pony large enough to ride today, instead of waiting at LEAST 3 years.
If you just want to experience pregnancy/birth/the miracle of life, volunteer at a rescue that takes in preggos, or find a local breeding farm in your area to clean some stalls in exchange for learning about breeding.
If you think it's "cool", or you want bragging rights to having raised a foal, think on this - when it's 4 am and your mare is laying there dying with a foal stuck in the canal, are you going to be able to drop the potential thousands in vet fees it's going to take to save HER life, even though you are losing the foal. How much bragging will you feel like doing when you have a dead mare and a dead foal - finding legal and affordable ways to dispose of horse bodies is an ugly reality check in the horse word as well.
If you just like dreaming out loud - state so at the start of the thread. No harm in dreaming, as long as you are aware there can be REAL harm in DOING.
Learn first, study, get help, and really open your eyes before you commit to breeding your pony.