I'm sure it will be a fun event to celebrate a birthday, and I hope you enjoy it.
Money isn't really and issue for us either right now--although I sure would like my mortgage to disappear.

We've been blessed with fairly secure jobs at the moment, and we like to save each year for a WDW trip.
For me (and I'm only speaking for myself), I could never see spending the money they're charging for something that doesn't seem like a truly special experience (to me). Maybe it's because I've been visiting the parks since 1982, and have had the pleasure of watching the fireworks from the terrace for free?

I guess, for some, it may feel like a private viewing of the fireworks?

I don't see them offering anything special. To me, it's like the expression--
you can put lipstick on a pig...to me, it's the plain old terrace with some fancy looking desserts in the mix. My personal feelings--This is the one-and-only time I've ever felt as though WDW is sucking the money out of people (and I'm one to pay for a good experience..loved paying for e-ride night, and would gladly pay again). I feel like they saw a great opportunity to make some money, so they jumped on it. I'm am a huge WDW fan, but this one thing puts a sour taste in my mouth. I'm not someone who normally watches from the terrace, and I've been wanting them to do more with the terrace in recent years. I just don't know that I like what they've come up with. It was a nice place for families to relax and enjoy a free view of the fireworks, and they've turned it into an overpriced moment...very overpriced.
I'm glad that some people love it, but I'd feel as if I was wasting money. I'd rather find one of my favorite park treats and watch for free from an equally good spot. Perhaps it's a great experience for first-timers, people with young children, people who feel crowded during fireworks, or those who want to slow down at the end of a long day. I'm sure it makes little girls feel like princesses for the night.
I'm not trying to discourage anyone from experiencing it, just explaining my thought process.