Uni of birmingham at 21 - will my A levels still be valid after 3 yearsv

Hi, this is my third gap year. I’m looking to apply for biochemistry at the university of birmingham, but my A levels will be 3 years old and I will have had 3 gap years. Will my a levels still be valid or will i have to resit them? I’m really scared that I’m not going to be accepted because of my A levels being achieved several years ago and having no study in these 3 gap years. I did achieve 3 A*s so I don’t think it will be the grades, more about the fact that they were achieved a while ago. Any advice would be so so appreciated!