Since you don't own one, I'd not bring one unless you really think you're going to need one. I would budget a little extra money for the trip just in case you find you do need one. (On the flip side, if you have one lying around or have a friend who will loan you theirs, then I'd take it just in case). The length of your trip will also matter. When our eldest was 3, he didn't need a stroller at all the first day. He was in it a great deal of time by the 7th day.
We will be taking a stroller for our 5 year old on our next trip. But my other two kids did not need one at 5. It was a lot of walking, but it's not straight walking - there are breaks for the attractions. My youngest needs a stroller not for physical reasons but for emotional reasons. He has some sensory issues and really needs a safe place to hang out. My middle child was in the stroller a lot during the trip we took when she was 3. It was a security thing for her - she felt safe there with all the people around her. So, also keep in mind emotional needs, not just physical.
*My eldest used to complain if he had to walk even short distances. On one Disney trip, he was 6 and he didn't have the option to use a stroller. (His last trip had been at 3 before that). He was too heavy for our stroller at 6 and the 3 year old used the stroller while the baby was in the sling. We told him that we would stay in the parks as long as the kids could handle. He did an amazing job walking! He had to keep up with the adults, as he was the oldest. We went pretty hard too - and he rose to the occasion. It's amazing what kids can handle when the option is handling it or going back to the hotel! (Unless they're really wanted to go back to the hotel. We do schedule in some pool time during our trips to take care of that).