An interesting question. I still don't have a proper answer for people who ask me this question in everyday life.
Basically it depends on the the temparament of the person. There are a few things which if you can follow will ensure that it's not difficult.
Ability to sit for long hours and memorise. - thee is a lot of info to learn and it continues throughout your life. Some of it is hard facts and numbers which make no sense but you have to learn them just because your body is made that way.
Interest- the most important thing. It will get hard at times and if you enter this field due to parental pressure or for money then you are gonna suffer.
Have minimal social life - if you are the type to go out every weekend with friends to clubs then you have to rethink this. Most weekends are for studying. Remember what you study will help a patient someday.
Hard-working - more than intelligence, consistent hardwork is the key to breezing through medicine.
If you can do these things, then you should have no problem . It's rather an enjoyable experience. Medicine is like no other field and of you are in it for the right reasons, you can find it very satisfying.
Disha Rajput, Medico