This is one of those things a child may not like, but you as a parent decide is best for them and you. It keeps her safe, she can't run off, and it offers a place for her to be while you tend to other things, like your walk tomorrow, you deserve to be able to get your exercise. Children can't always have their way about things, you explain that she needs to sit in it, period, it isn't a choice on her part...unless you know she will stay by your side and never wander away, will come immediately when you call her, hold your hand without fussing, keep up with you on your walks, and not need a nap and require you to carry her. You could also leave her with a sitter or not go on the walk. What is practical and realistic for you?
My guy turned 3 last week, I have 2 strollers, and took one when we went to Disneyland on Thursday. He may be big enough to walk all around the park, but I know he still needs to sit sometimes. Fits/tantrums I discipline, he had 2 time-outs at Disneyland and survived : ) And I take a stroller for him on some walks still.