Used Forester questions

[seanpwilliams98]

I recently bought a used 2018 Forester with 34k miles. I've noticed a couple things that somewhat worry me.
1. The car seems to struggle to turn over sometimes. It still starts, but it is slower in the process. Could this be a dying battery?
2. The brakes squeal when stopping. It doesn't happen all the time but most of the time when slowing down at higher speeds they'll squeal pretty loud, loud enough to hear over music in the car. Do I just need to spray the pads?
3. The car sometimes take up to 2-3 seconds to switch gears from drive to reverse or the other way around. Could it be transmission fluid issue?

Thanks in advance for any answers.