Is 4 Too Young For Kiddie Songs On MP3 Player (speaker)?

My husband and I took my daughter to goodwill with us and let her get a toy. She picked out a pink dog that lit up and barked. We thought it was some kind of robot dog. She really wanted it and it was only 2 dollars so we let her get it. She is 4 years old. When we got home we realized it was speaker for an MP3 player. We had a little usb mp3 stick laying around and put some kiddie nick jr. songs on it (like dora and backyardagins) and let her have it. My question. Do you think shes too young for this kind of thing? I dont know, but my husband thinks its fine, what do you all think? I know that I would have never had an MP3 player at 4 but times are different now and technology has advanced so much since the 80's lol! Thank you in advance for any answers! :)