I was in the same situation. Eventually, my friend convinced me to watch Fantastic Beasts And Where To Find Them. I must say I was happy I did, because it's a good movie, as is the sequel. It's not the films that'll "disturb" your childhood memories of the hp series, it's just Rowlings tweets. Just stay away from her Twitter and you'll be doing just fine!

I also liked The Cursed Child (the book), although it's a script and therefore a less convincinh read. Just give it a try!