How to organize group events

I am annoyed.
I should not be nearly as annoyed about this as I am, but I'm just that kind of person.

Back in September, probably about the second week of the course, it was suggested we come up with some exciting group event. Two ideas that were bounced around were:

a) whale watching
b) horseback riding

I believe price was the deciding factor, and inquiries about horseback riding began, or... should have begun.

To be fair, horseback riding was my suggestion, as I had seen a sign on my way to school advertising trail rides and I personally would enjoy a ride through the forest here. It was, however, the person who suggested whale watching who volunteered to call the place and book a trail ride.

Two months later, long after the pleasant weather has ended, on a Thursday afternoon, said organizer decides to go around and see who is actually interested in going for that trail ride. I say sure, count me in, and then don't worry about it anymore. Like I said, I wasn't the one organizing it.

So, yesterday, Saturday, I get this text message. She wants me to call the trail riding place, saying she can't get a phone signal (so, how did she text me?). I agree, and text her back asking her to email me all the information. Now, in my mind, the information required for such an event includes things like the name of the place, the name of the person I am calling, the day she wants to do this trail ride, and how many people I am making a booking for. That last point being one of the most vital, because I can't just show up with nineteen people and expect to have her saddle up nineteen horses without notice, nor can I show up with two people, when she has already saddled nineteen.

What I get is a phone number, that she wants to book for the next day, and that "a bunch of people will cost $35 each".
That's great. So, you want me to book a place with less than 24 hours notice, I have no idea who or where I am calling, and I tell them that 'a bunch' of people are interested?

So I call the place up. Explain that I am calling on behalf of someone else, and that I have very little information. I check that a date in one week, not one day, is clear. I get a time. I ensure that she has enough horses on the off chance that everyone in the class would like to go. Then I tell the lovely patient woman that I will call back and confirm numbers on Monday. Then I send out an email to the class list, giving the date, time, location, and price, along with the Monday deadline for RSVP.

I did, in five minutes, what took the other person to do in 2 months. This is how you plan and book a group event, folks. Set a prospective date with a minimum of one week's notice, ensure the venue is available and able to accommodate your group, inform the group of the date, the location, and the time, set a dealine for RSVP, finalize the reservation with the venue ASAP.

Most importantly:

Don't pass the buck to me! I don't like doing it!