She definitely is stubborn and that doesn't help with getting her on the bit, but she might also not understand what I am asking, but I'm just going to leave it for now
Consult an instructor, it may not be that she is stubborn but rather doesn't understand what you are asking, she is still very young☺️
Try vibrating your fingers when trying to get the pony on the bit
I feel like an idiot now! I would never want to do that to my beautiful girl! Thank you for telling me this and I will defiantly do the circle work!
As a five year old, you shouldn't expect him to be on the bit already. I know that those lovely 3yo ponies presented at auctions look fabulous under saddle, but trust me, just don't expect to achieve that before he is 7yo and under no circumstances without consistent training. By not allowing him all by himself to seek for your contact but rather forcing him in a position, in almost a year you might end up having a literally broken horse, with back problems, broken in his neck, no self carriage, no elasticity, which translate intro a horse which cannot show quality performances.
To answer your question, be patient everytime, show her understanding whenever she reacts and encourage her to follow your instructions on going forward. Introduce circles for the beginning, make them more complex by turning them to figure 8 and later on other figures. Ride with your seat and legs, forget about the hands (horses are not bicycles, I always say). Use half-halts, as they do make your horse more attentive to you and they always rebalance you. Do not forget the transitions, which really work wonders in combination with half-halts.