Dear aspirant,

As you have mentioned that you haven't studied chemistry beyond chapter 3 in std.11. So, I would like to make you aware of the following situations.

1-If you are not planning to do engineering and want to opt for some other line like bsc+msc or some other line, then it is absolutely allright because you won't need Std.11 chemistry.

2-If you want to go for engineering then you have to go through all the chapters that you have missed in your Std. 11 because in all engineering entrances questions from both classes which 11th and 12th are asked.

Now, it is upto you what line you are taking up.

I hope my suggestions helped you!!