First of well, please dont be so negative and do not skip the exam as still you have time to prepare so focus on that properly or if you talk about IIT admission then you will have to appear in Jee main and advanced and for that your 3 consecutive year (Jee main) and 2 year (advanced) when you are in 12th will be counted so in case you drop this year or dont sit in exam then your 1 chance will be deducted for both and you will be considered as fail candidate so please dont do that.

Good Luck!!!