They are both “medical” fields and similarity sort of ends there.
People choose to be physicians for various reasons.
Some reasons are: intellectual stimulating, helping people, financial security, job security, prestige, family expectation, life experience, people told them they’re smart.... etc etc. For me? probably combination of all these. It’s very hard for some people to find the “right” reasons, for some they may not know the right reasons until much later in life or even well into medical training. You’ll need to find the right answers yourself.
Why do you want to be a pharmacist? Do you know what they do? Do you enjoy certain parts of their job? Do you dislike some parts of their job? You should go through that with any fields that you consider. It’s not always easy and clear, especially when you’re 18.
I will tell you what I tell anyone who’s considering to become a doctor, if there is something that you want to do, try that first. Medicine is a rewarding, challenging and for most people a long unyielding journey.
Good luck.