Am I able to get into UCL, Queen Mary's or Imperial with 2A* 4As and 5Bs?

what course?

Those GCSEs are fine, assuming you meet any specific requirements (Such as a B in Maths).

Okay, I got an A* for Maths, a B in English, but from all the students I've heard from they've received A*s for nearly all of their subjects, so I'm really worried

No university requires that many A*s, though how important the are depends on the course you are applying for and how competitive it is.

So would medicine or a dentistry course be difficult due to competitiveness?

So would medicine or a dentistry course be difficult due to competitiveness?

Imperial don't have GCSE requirements for their medicine course. They focus primarily on the BMAT.

Well both are highly competitive, but there are other ways, with those particularly, to make yourself stand out. Your GCSEs are fine, but work experience, good performance on medical tests, and great A-Levels will make you stand out.

I would love to have an honest opinion.

I think you can get into those unis, providing you have the minimum grade required for a-levels as well. I am currently in Year 12 and I got 3A*,5A and 3B. I also have an interest in those unis too as I want to study medicine. Not only a-levels, but you also need a good BMAT (or UKCAT) score as well as a variety of work experience.