I too like lunge lessons - but at the end of a lunge lesson my RI would unhitch the horse and just leave me alone to control the horse. Lunge lessons are often quite fast - and the other speciality of that school was to work in walk off the lunge. That is how you can gain confidence - walking your horse, breathing deep to relax yourself and the horse, feeling the movement of the hind legs thro your seat, giving her something to think about by steering her - riding corners and circles and weaving through poles. But all in walk. Breath deeply and relax. Ride halt walk transitions using as little rein and leg as possible, reducing your cues. Teach her to stand while you mount and dismount. And not to move a off till you ask. And possibly then after two or three weeks when you know each other you may be ready to ask gently for a little trot - on a 20 metre circle. I would do some ground work too on leading and halting and then trotting up (which is part of the BHS stage One stable management). A horse that lstens to you and respects you on the ground will be more likely to listen when you ride. And I agree, I prefer a bigger school - more space between the corners.It is harder to balance going round corners at speed. But then for years I did little in my lessons except walk and after any scare I would go back to the school and start from square one, doing all the walk exercises over again.