It's totally your choice if you go or not. I've had wonderful trips with that age child, but they're done at the child's pace, and centered around the child's needs/wants.
A few suggestions, if you choose to go:
Keep to your regular schedule, as much as possible. This might mean you miss the fireworks each night, in order to get her in bed at her regular time. That's okay--you'll be back.
If you make a threat, follow through if necessary. If you say, "One more outburst, and we're going back to the room", then follow through. Hopefully, one time will send the message you want.
Aim the trip to your child's level. This might mean running on the grass or doing Dumbo three times in a row. Character meals are great at this age.
Look for signs that your child is overwhelmed or overstimulated. These might not be the signs you think! When our niece was little, she wouldn't poop for 5 days in WDW. She also stayed up too late, too many times, and wound up sleeping in her stroller for the entire "Magic Kingdom Day". Meanwhile, one of my kids found, at age 3, that if she wet herself, she would be immediately taken out of her current situation. This was her "escape route" when something seemed scary. Man, I wish I figured this one out earlier in the trip!
Always have snacks available, plan plenty of potty breaks, have a back-up plan or three.
You can have a magical trip, but it may be different than past trips. Or, you can choose to put off the trip, and have a magical trip in the future. Postponing does NOT make you a bad parent!