It's too difficult to go to Oxford University with a junior college degree. Postgraduate entrance examination is optional and a relatively safe direction. After passing the postgraduate entrance examination, you will be admitted to the relatively top universities in China. At that time, the platform will be higher and your chances of studying abroad will be greater.

If you can graduate from key universities in China (the so-called "985 Engineering College" and "2 1 1 Engineering College"), your platform will be much higher than you are now, and it will be easier to study abroad. However, in your current situation, although the direction of postgraduate entrance examination is feasible and relatively safe, it is not difficult.