Caroline in season 4 went on and on about the Stefan diet and how Elena should go on it but Caroline isn’t even on the Stefan diet. she drink from blood bags. what do you think about this?

I believe that she is trying to be good to Elena.. But I think she should let her decide.

Caroline has the most control over herself on the show. Yes, in the beginning she killed someone, but of course that was gunna happen, she was going through something terrifying & disorienting without any knowledge of what was happening or help from anyone. Since then, she's been perfectly stable, even while drinking human blood. Elena on the other hand is a complete mess. She needs everything to be perfect in order to keep in check. If anything goes wrong she falls apart. That's why Stefan never wanted her to turn, he knew she wouldn't be able to handle it. Even as a human, she was way too emotionally brittle. Amplify that by becoming a vampire and you've got a time bomb on your hands. Human Elena over either versions of Caroline. But vampire Caroline over vampire Elena for sure.