17 years old with a L5-S1 disc Herniation

So I've been dealing with sciatica for over 6 months but didnt do anything about it for a while and just hope it would go away. And just today I got a MRI scan and the doctor told me that it was a lot worse than he thought and it was severe. Sadly I dont have a picture.

But the thing is it honestly doesnt feel that bad I obviously have sciatica but its just mild and im still able to walk for hours, sit for long periods of time, and overall just move around "fine" albeit with some mild pain and discomfort.

My orthopedist said due to my age surgery should be the very last option only for when the pain is super unbearable or if I experience urinary problems/leg drop. As of right now I got a injection which the doctor said would help with the pain and he prescribed me some stronger pain killers. He just told me to continue to fix my posture and do core exercises. While also making sure to go for light walks and not sit for too long. This all easy enough to do because I am in summer break however I will start university in around a month and will have to move around a lot, sit for long periods of time, andmay be less consistent with my core exercises.

Will following what my doctor say help fix my disc? And how long will it take for it to fully fix or atleast for the pain to go away?