My first one was a Samsung Galaxy S1 that I got in 2013 and it was a great little device that was easy to open up and repair. It had only 512MB of RAM but that was plenty for basic phone needs, web browsing and running some Android apps like AnkiDroid at the time.
i can’t remember if i got the htc one or the nexus 4 or 5 first but i believe those were the first versions of android i used. i think i was doing ios up to ios 7 maybe??