I need to take physics to get into the program I prefer next year...I took grade 12 physics, and I did decent but this was like 4 years ago. The only thing open is 1b03; is there anyone out there who has taken both and can comment on how hard taking 1b03 is? contemplating dropping it and waiting until next year to take it

If you need it to get into the program that you want, then just take it. If it turns out you fail miserably at it, you can always drop it later. Do give it a good effort though; revisit your grade 12 notes, go to office hours, ask questions, etc.