I don't know what your situation is, or why your trainer feels you aren't ready to lease a horse. I can only say that, when it came to my owning my first horse, for 20 years people told me all the reasons why I shouldn't do it. I finally ignored them all, got my first horse at age 40, and am really ticked off that I listened to any of them!!! Getting my horse is the best decision I've ever made. If you really want to lease a horse, do it. Find a horse that you're comfortable with and just do a one month trial. If it doesn't work out, at least you tried it.