Hello aspirant!

Do not worry!

Engineering is very different from 12th. Some of the topcis you studies in 12th and 11th will appear in engineering too. But you will learn a lot of new things as well and it is not really as difficult.

In math, you will use a lot of integration and differentiation you leant in 12th for topics such as fourier series and transforms, laplace series and transforms etc. So revise your math formuale, integration and differentiation once.

In physics, you will have quantum physics, wave physics, optics etc. Revise photoetectric effect, ray and wave optics, a bit of quantum physcis as well.

Coming to chemistry, you will learn about polymers, water treatment and chemicals, electrochemistry. and other extended topcis. You can revisit those PU topcis once again.

Rest do not worry! It is very easy compared to 12th.