Do I need to go to a performing arts school to become an actor?

I mean to encourage, not discourage. But... the fact that you are asking this question tells me you need to go to school. Will the Internet teach you to act? Not just in your private room... but on stage, on camera... opposite a scene partner... exchanging dialogue? Will the Internet teach you how to deepen your emotions, to use relaxation? To Play a comedic scene opposite a partner? These are acquired skills. You are seeking short cuts. Will the Internet build your 'face-to-face' business network? Forget Performing Arts School- Aim higher. A University Degree from a school with sustained excellence in 'Higher Education.' Ivy League, Julliard, Harvard, Yale, Northwestern, NYU, Carnegie Melon, UCLA, Stanford... Great grades in High School may earn you a scholarship. Abilities in sports ... or by auditioning for an institution of higher learning may earn you a scholarship/ work scholarship. You will need a well rounded education to be a well rounded actor/singer/musician/etc. Watching a musician play 'scales' or a vocalist sing... will not give you the practical working tested performance skills you will need in the marketplace. If you take 'short cuts' ... the only person cut short is you. Aim high! Read, read, read!!! Literature. Study Literature, Languages, accents, music/an instrument/ philosophy, computer skills, marketing, business and business law. (You will need it all in the professional world.) Best of luck.

Your question is loaded actually. No, you don't NEED to go to performing arts school.

But do this: research your favorite actors working on TV, film or theater right now. See what they did. If they are the kind of actor you want to be, see what led them to their careers.

When I was in high school, I started looking at bios of the plays I attended, and so many of my favorite actors had an MFA. At that point, I didn't know what that was, but I was going to find out.

Let your instinct guide you. There is no one path, but I think you'll start to see some common elements.

A successful career in acting requires equal parts talent and practice with a bit of luck thrown in.Although an acting degree is not always necessary to land acting jobs, it can be very helpful.
Anyone interested in an acting career should consider a degree from one of the many acting schools around the world. Whether you just have a love for theater or you want to become rich and famous, polished acting skills will help you in your career.Practicing not only lets you do what you love, but it also helps you fine tune your skills.
Talent scouts and acting agents also regularly haunt acting schools as well, so a degree from an accredited acting school can help you get noticed faster.

There is not a "right or wrong" path to start your journey. Only you know what is best for you. Many successful actors continue to study their craft. . Knowledge is power, and there are many venues to receive that knowledge. Best wishes.