Is it normal that when I was 15 I had almost invisible pores, now that I'm 18 my pores look huge and I also have tons of acne?

It depends. If that was an overnight change (think days), then that's not normal. If it was a gradual increase then it may be. I would have to have the answers to more questions such as:

Are you overweight? Do you have allergies? Are you on any medication? Did you have a round of boosters before the outbreak began? What is your diet like? What is your activity level like? Do you ever see the seriousness decrease, and if so for how long and when? Do you have anxiety?

Etc.

But, in the meantime - you could see a dermatologist. Have you thought about it? What stops you?

My worse acne was at 18 if I remember well... Also, a higher stress will trigger your acne (things like starting university, living on your own etc).

yes, that's normal. you might legally be an adult at 18 but your body doesn't know that lol. acne will come and go throughout your whole life (for some people more than others) based on stress, your period, pregnancy, meds, etc etc.

if it's any consolation, and maybe it's the camera, but your pores look very small to me. i've had huge pores my whooooole life and i just recently started a new serum to try to make them smaller. no luck yet but ngl i don't use it nearly as much as i'm supposed to 😬