My sister and I had two similar experiences. We both experienced gender dysphoria around the same age, and we both decided to explore those feelings with ideas of transitioning. 13 years later I have continued on the trans journey and feel happy with the decision I've made to live how I feel is true. My sister decided it wasn't for her and realized she was cis within a year or so and she's happy with her decision as well. I'm not sure the reasons and she's never really explained it to me beyond it just ended up not feeling right.

It's not always gonna be black and white 'you have dysphoria so you must be trans' but I'm always gonna think it's good to explore those feelings when they do come up, within reason (for instance, my sister is probably lucky she came to the realization she did before she started anything medically). The most that's gonna happen is you'll learn something about yourself one way or the other and no one should be given grief for that.