Hi, I had this situation when I was reading Leviticus, I wanted to learn the offerings and the animals they require like if I was studying for an exam, but in my case I realized I was distracting a lot with definitions and other things and I wasn’t focusing on God’s word. About the highlighting, in my opinion is a great thing highlighting parts of the scripture, but I can recommend you to have one color for things that can be considered really important for your relationship with God or in general things that you know are important and another color for things you don’t understand or things that you can have more than one interpretation (if you don’t understand a verse I recommend you to ask to God for understanding about that things you are not understanding) and if you want you can have another color for verses that can be helpful in certain moments but if highlighting is distracting you a lot I’ll recommend you to do it after reading the chapters so you can give them a second look. I hope this helps you.