Dear Abhinandhan,
There is no consequence as such! But, even if you are not prepared for the exam, please do appear for all the exams.
Is three month period sufficient for preparation of eight subjects? Yes and no, both. Its better you start preparing in advance. Last 3 months should mostly be used for revision.
My advice, don't mix-up Industrial training and CA final preparation. Look industrial training as a new assignment (but don't compromise of negotiation for leave for exams). Also, if you attend tuition classes honestly, they won't go waste. Look at an alternative scenario - what if you don't go for industrial training and continue with the same firm with and attend all the tuition classes including for DT and IDT, but fail to clear in the first attempt! Even then you shall have to update yourself for changes in DT and IDT!
An honest preparation should start now. Your first attempt is 9 months away! More than sufficient for any preparation. If you are afraid of DT and IDT, start with them first. Cover the basics (which normally don't change) first and then update yourself with the amendments a month before the exam.
Make sure that you cover, ISCA, Costing, FM, law and audit before you go for CA Final leave.
In the nutshell, I am all game for industrial training. It gives you a totally different exposure and gives u a lot of professional experience (something which mid-size CA firms often lack).