while i haven't read all the comments i want to say this, even if it's been repeated already. you NEED an instructor.
let me tell you why:
i was big time into horses from age 10 to age 20. owned my horse, boarded, exercised others horses, helped run a boarding barn with lesson program, etc. i was good in my own mind, had good balance, was able to ride a number of different horses well, and rarely came off. my lessons at age 10/11 were not much past beginner - meaning pretty much walk, trot, canter, small little jumps. after less than a year of lessons back in the day i moved on to leasing then owning. this was pre-internet, so i thought i knew a lot.
took a 12 year break from horses.
did not get back into it via lessons like i should have. instead i leased a horse that belonged to a friend of a friend. said horse was a big calm lumbering beast of a draft cross. the kind you could watch a cat climb up it's stifle and it would yawn while that happened. best horse to get back into riding with.
i had that 'i rode before, i know what i'm doing' attitude.
switched leases. new lease was a quarterhorse that had been there, done that, and was a steady eddie type. i was still in a comfort zone and my riding self esteem was still sky high. this was due to the horse under me being compliant and not giving me problems.
then that lease ended and i bought a young mare that wasn't trained. i thought i could do it, train that mare, and we'd go riding off everywhere together just like i did with my old pony gelding from my teens.
i was WRONG. i needed lessons. i needed to learn that i was not in the same place i was when i rode before. i needed to know that although my knowledge was there, my body was not equipped any more to put up with the issues that can arise when handling/training/riding young green/not yet fully broke horses.
my mindset was still in 'i'm riding a trained horse' mode. my horse was not a trained horse although she gave me moments that felt like she'd 'been there, done that'. this was my error. i've slid back a LOT psychologically in my confidence because of my error.
now i have a horse that is not fully trained nor ride-able (but our trainer is helping with that) and i have a humble appreciation for those out there that help us idiots learn how to ride properly and effectively. I still have not signed up for lessons. i need to. in order to help me ride a horse properly, safely, and effectively.