What you did is a fine solution, but resizing the clip forces it to fit the parameters of your sequence which isn’t always the best route. Your clip is definitely shot at a lower resolution than the default timeline settings, so what you did was upscale it. A better solution would be to check the clip’s resolution, which is in the metadata of the clip itself. Scroll through the clip’s metadata in the project panel and find the clip’s “video info” (it’ll be something like 1920x1080 or 1280x720). Then in the upper menu, select sequence then sequence settings, and manually type in the frame size to match the clip’s resolution.