Is it bad for a 19 year old to fall for a 14 year old in the UK?

It's not bad as we cannot help our feelings. It is what you do about those feelings that can be bad, not just bad but illegal. So to keep on the right side of the law, it's best to keep the feelings to yourself, until the person becomes 16 by that time you may not have the same feelings but if you do, the other person will have attained a sufficient age of consent to decide for themselves, without causing any legal problems for you. Child protection and safety laws in the UK are very strict. Another way to overcome these feelings is to look for someone around your own age group were you will have no problems with the law.