Jeg vil gerne lære dansk

Dansk er et interessant sprog. det er svært at udtale. Jeg kan godt lide lyden af dansk. Jeg har en dansk ven. Jeg har kendt hende siden vi gik* på universitetet. Jeg studerede musik. Jeg spillede bratsch og fløjte. Jeg kan ikke afspille** musik nu. Nu underviser jeg mine børn derhjemme. Tak!

Notes

Really great, keep up the good work! Not much to correct :)

* What you wrote can definitely be said, however we would likely say "since we went to university" instead, and as such it becomes "siden vi gik på universitetet".

** I'm unsure what you're trying to say with this sentence - it might be correct, it depends on the meaning. What it means in its current context is "I cannot play music (as in, playing a record, listening to a song etc.)". It implies you're playing someone else's music on a music listening device, in order to listen to it.