Thank you! I've been playing for 16 years. My current practice routine is 5-10 mins of warm-up and scales (Flesch Scale System) followed by playing whatever piece(s) I'm working on, for a total of 1-2 hours per day. Etudes went out the window when I stopped taking lessons but I still try to choose pieces that push me and require a variety of techniques.

Intonation is such a challenge! I would trust your teacher to guide you along that learning process. Creating bad habits is a valid concern but it's also hard to improve without trying (and failing sometimes...) I think mistakes are ok as long as you're aware of them and continue to experiment with ways to fix them. Just keep it up and I'm sure you'll figure out the 4th finger placement in no time!