My best friend is being a brat!!? Help!?

About two months ago, for my birthday i suggested we go pony trekking together, and then go to the small water park in our town with our other two best friends. Everyone agreed. But now my friend has texted me to say that the water park i picked is two small and only has two rides, whereas the one about an hour away, which is double the price looks better. I said if we go there, we can't go pony trekking because then that's too much money in total. And I said it was unfair on my mum, because then she will have to drive us an hour there and do something in that city for a day while we swim. My friend is now not replying to any of my texts. Is she being a brat? Or am I being unfair?