Hello. First of all you need to fulfill the eligibility criteria for FMS Delhi which is you need to have a bachelors degree in any field with an aggregate of atleast 50% for general and 45% for reserved category students. Also final year students can apply provided they fulfill the criteria. Since you are currently in 1st year of B.Tech you oviously cannot apply for FMS Delhi now.

But if you study hard and score a percentile of 97+ in CAT you might get you a seat there.

For more details about cutoff, eligibility etc. check the below link.

https://www.google.com/amp/s/bschool.careers360.com/articles/fms-delhi-admission-criteria-2018-20-60-cent-weightage-on-cat-score/amp

Hope this helps. Good luck!