I will say as an instructor who has her students tack/untack for every lesson it can take some time to do so. We supervise every student while they tack up because many of our students are very new to horses. Our newer and even the experienced young clients take a bit longer to tack up, if they dawdle they lose riding time seeing as they are paying for an hour total with the horse and I. I'm thinking someone tacks up for you because if you had to learn to groom/tack/untack/groom in half an hour you'd have very little time to ride if any. A pony day or something of the like sounds like a good idea before you just hang around the barn offering to tack horses if you're not sure how.
Also, weather sucks for riding. I'm in southern California teaching in a rather rich area with horses, and many of my students are little girls 6-10. Parents sometimes don't drop off their kids because it's rained the day before and they assume things are cancelled or the parents don't want the kids muddy or whatever. We still offer "trail" rides and chances to learn about tack and such and we get stood up all the time which leads to my boss sometimes cancelling simply because our clients don't come. I have to imagine other barns do this.
And as for group vs private lesson...if you're feeling relatively comfortable on the horse, I see no issue stepping up to a *small* group lesson. Our groups means there's two riders in the lesson. It'll give you more time to ride and you may be able to, at the very least, have your instructor go over the tack that is already on the horse with you. Posted via Mobile Device