Where I live, lessons vary from $35/hr, up to (wait for it!) $75/hr-! During the $75 lesson, the (rude to begin with!) "instructor" spends the whole time texting on her phone, per my very reliable source-- AND THIS IS AT A BARN which CHARGES $750 per month to board!!!!
As stated by Corazon and Horseless, it is therefore VERY important to check out the barn before you sign up for lessons!! It just goes to show that even at the "super fancy" barns, the lessons are not by any means going to be better than at other barns!
By the way....my lessons are $35, they last "as long as it takes", meaning, maybe 1 hour, maybe 90 min of saddle time, plus before and after horse and tack care "lessons". My trainer only takes on so many students so she can really be sure sure gives each one what they and their horse need to complete the learning process for that day and end on a positive note, regardless of how tough the lesson (for most have their own horses and board there, whereas I ride one or the other of her personal horses).
The REALLY interesting thing about this long story is that these two stables (the $35 & the $75 lessons) are just about two miles from each other, are EACH are multimillion dollar facilities (gorgeous!) & both are primarily dressage barns, so lots of money in their horses and breeding, etc....(I am FAR from wealthy, I just happen to live somewhat near these stables!). Anyway, at the super-expensive barn with the texting trainer, you FEEL NERVOUS just walking onto the property...like, there is a negative "vibe", as per myself, my husband, and my friend who I volunteer with.
On the other hand, as soon as you set foot on my trainer's barn property, you feel AWESOME, ready to learn, everyone is open and friendly and she greets everyone with a hug if you are a "hugger" or a big wave if you aren't! :0)
My point with all this...good training at the RIGHT BARN (whatever that means for YOU) will DRASTICALLY EFFECT how much you enjoy the discipline, the actual riding, and how fast you learn. You, at 17, will be spending your own HARD EARNED MONEY, possibly for the first time ever, so it's really important you learn how to be a choosy consumer, and only spend your money if it is worthwhile and makes YOU GAIN SKILL AND FEEL GOOD!!
Very best of luck to you!!!