Hey! I'm currently doing Bio and Methods 3/4 in Year 11 (which is what I assume you want to do)
Bio is an awesome subject (at least for me!) It is easily my favourite subject, and I did Unit 1 in Year 10, but didn't love it, I think partly because of the teacher. I reckon give it a go, or at least read the study design to see if it interests you. If you find that it doesn't interest you, however, I probably wouldn't recommend doing it, as I know some people who don't like the subject and hate studying for it.
As for tutoring, I do get tutored for Bio, but I 100% think its unnecessary, especially if you have a good teacher. For 1/2, you definitely don't need it, but if you're finding concepts hard to understand, then give it a go.
Methods 3/4 in Year 11 isn't to difficult, especially if you are good at maths and are getting tutored. Methods is basically just maths you've been doing you're whole life, but learning to apply it a little more. I would recommend doing Methods in Year 11 as you have much more time to dedicate to it, and will probably do better in it.