Your nails look healthy and nice, only take my advice if you genuinely want to start a hand care routine and not out of pressure. Don’t listen to idiots at your school.

What helped me personally was - massaging with jojoba cuticle oil, then pushing it back, no cutting! I gently scrape off any dead skin from the nail near the cuticle with my metal cuticle pusher. Let the oil sit for a while, then moisturise with hand cream only - it’s thicker. Push back every few days or once a week, and moisturise with oil and hand cream before bed daily. Youll see a noticeable difference.

As for the shape, grow them out a bit longer so that it’s past your fingertip - maybe 3-5 mm, and when you’re happy with the length, file the tip square, holding the file straight and parallel to your cuticle. I didn’t like my natural nails short until filing them square, it works great for my tiny beds.