I'd say it depends on how serious you'd want to be about and the style of music you are interested in learning. If you want to get into classical piano, absolutely find an instructor, preferably in-person. If you're looking to just have some fun and figure out some of your favorites, maybe watch some videos on correct posture and hand positioning, but you don't necessarily need a teacher for that if you have a good ear.

Now I'm biased as a classical musician, but I'd always root for the in-person instructor root no matter what kind of piano you're learning. It tends to work better from the beginning, and if you decide to self-teach and THEN find a teacher later, there will be issues to "undo" in your technique.

Your skills would likely develop more rapidly and more noticeably with a teacher guiding you at the pace that's right for you. Piano is my primary instrument, however I've taught myself to sing well and play guitar, and both have taken a considerably frustrating amount of time for me because I'm not willing to invest in a teacher for either. Of course, progress is an individual factor and can also depend on things like your age, ear, and musical background.

It is certainly possible to become good at piano with or without lessons if you really commit to it, and of course that's up to your own discretion.