OP, Glad you think this is a not so bad place!
Most think the same.
It can be hard for some trainers to be honest to their pupils. A horse they might have and is perfect for them they can genuinely think would be ideal for you.
What they fail to test is riding the horse as you would for several days to see what advantage it might take of a less experienced/confidences rider.
I was often asked to go sort out problems with a horse balking. I could get on that animal amd it wouldn't try a thing. What I learned to do was to not correct the little things I normally would in the stables, to allow it to walk out the door before being invited, move when I mounted and then I would sit on it like a right numpty, let it amble along even snatching grass and the whole time getting myself to think it was going to mess around.
It worked. The horse would go so far and then try it on. I would be ready, it would get a quick and hard correction, amd we would go on with me riding like a numpty.
This taught the horse that just because someone wasn't a strong roder never gave it the right to take advantage.
I say that problems in the saddle more often than not stem from on the ground problems. The fact the mare kicked out at you in the field shows she has little to no respect for you.
You need to learn how to deal with the little on the ground things.
You will find a lot on ground work in Training section. Most of this is getting a horse to respect your space. I go further than that and start in the stable.
A horse has to stand untied where I tell it. Usually at the back of the stable. If it takes a step forward it is pushed back to where it was.
If I open the stable door it still has to stand and wait for me to tell it to move.
When I enter a stable I expect the horse to move back to give me room. These are two very simple things, it doesn't take a lot to get them obedient to this and because these two little things are corrected rarely do they try much on when outside.
Good luck to you!