yo, I like what youre making, and I liked the paint on the back. Be ware though that tattooing is very very difficult and stuff like this is next level stuff.. You should only start thinking about doing a big back like that after 1,5 or 2 years of tattooing or else you will fuck it up.
That being said, I think youre drawing a bit out of your league. I like the motorbike, but this is also super hard to tattoo – actuallly its pretty untattooable due to a lot of reasons in the design. A good drawing is not automatically a good tattoo 🙂
If you really want to learn stuff in these weeks, I think you should do smaller simpler stuff, and do more of them. Buy tattoo magazines and books and focus on 1 thing: like roses. I see you like the realistic stuff so just draw roses or butterflys for a month… And try to make a nice one each week. Trust me, doing it like this will feel sloooooow but is actually fast fast fast!
Your art is good but if you want to tattoo, make tattoos! Just small ones! Focus on roses, butterflys, script and make sure you get a good solid apprenticeship.
All the best!
Vince