Hey Diode,
I haven’t used Audacity myself but know many people are very happy with that software. Definitely a good place to start!
I’m a Cubase guy, and I can atest to the fact that Cubase is EXTREMELY user friendly. So if you ever want to pay for a DAW, I’d recommend trying it out. You could probably manage fine with their cheaper “Elements” or “Artist” versions too.
What kind of music are you wanting to compose? That can sometimes matter with what DAW you choose too.