Which field you are most passionate about? Can you work day in and day out on a given task and not miss otherworldly pleasures. If yes, you arre headed in the right direction.
Even if you are passionate about a particular field, you may lack certain skills to excel in that area. Determine if you have the right set of skills to work in the field of your interest.
The devil is in the details. A certain field may seem very interesting until you find out what actually it involves. The job of a robotics engineer seems very interesting. But when you find out the details you will see it requires understanding of material science, advanced mathematics and physics, you may or may not be interested to study those. Understanding your field of interest in depth will give you a clarity for taking decisions.
The boring tasks
Event the most interesting job that you are passionate about, will involve a lot of side tasks which may be monotonic/ uninteresting and difficult. Find out what those are for your field of interest. Talk to people in industry who have at least 5-10 years of experience. See if you could power through those uninteresting jobs to work on something you are passionate about.
Find out which field is going to boom in future and which may go obsolete. Again you need to talk to industry experts to get some understanding of where the industry is heading. Find out what all career options you have if you choose to study a particular subject. There are a lot of jobs that exist today which may get automated tomorrow and will not require human intervention. You may want to avoid such fields.