Usually, violin is a kind of instrument that you start at a young age. The default time to start is fourth grade. Our school system started in second. I’ve been playing for 7+ years now, and have been taking private lessons for 6 years.
That being said, anyone can learn to play the violin, although it is easier if you start at a young age.
You will want to hire a private lesson teacher, because violin involves a lot of technique such as hand position, making quality bow strokes, vibrato, etc. and a teacher is very much needed so that she can enforce your quality of these techniques.
Violin is a difficult instrument to learn how to play because not only is there a lot of technique that is very critical usually all the time, but the musicality and how you play the piece matters almost equally as much. So essentially, it’s very hard to make it sound good.
So I strongly recommend getting lessons. Most good teachers will teach at a dollar/minute. My teacher offers 30 minute lessons for $30, 45 minute lessons for $45, and one hour lessons for $60. And usually, when you sign up for lessons, the teacher has to accept you. Usually they don’t just take you. The typical frequency for lessons is once a week. And for your first year, you’ll probably only need 20-30 minutes a day, 5 days a week of practice. After that, you’ll probably want to do more. However, you’re teacher will guide you through that. I “should” practice more, but I don’t :D. Apparently though, I still play excellently according to my teachers.
Now as in finding a “good” teacher, like I said, the rates should be close or slightly lower than that. If the lessons are really cheap, chances are, you’re not going to a very good teacher. My teacher says that unfortunately, most violin teachers don’t focus too much on technique, only a few do. One of those teachers are mine obviously. My teacher is really critical on technique, which is a good thing.
However, if you’re just starting out, cheap lessons should be fine, but after your first year or so, you’ll want to find a more expensive teacher who can sit with you for 45 minutes to an hour a week and guide you through everything more critically.