Decided to finally gain some weight

Hi , I finally decided to gain some weight , because I got sick of always being the skinny “kid”. I am 20 yo and I have some questions, and I would appreciate it if someone could answer them.

Firstly , because of a busy schedule I can’t get a lot of meals into my daily schedule, so I am trying to get those calories by drinking smoothies. I drink the smoothie 2 times a day , and each one is about 800 calories.

Secondly , without being 100% sure I am guessing that I used to eat around 2k calories a day. Will there be a problem if I suddenly consume 3000-3500 calories daily ? ( 700 from breakfast ,1600 from the smoothies and the rest from lunch/ dinner)

I know that my questions may seem stupid or something , but I want to get to a normal weight , as I will start going to the gym regularly as well.

P.S. : I will be asking a an expert as well, but I would like to know if anyone had the same questions as well in the past , and if he/she knows the answers to those questions