No it is not weird to be a year older than anyone else. When you get to Uni people will be a wide range of ages. In the workplace you will be amongst a wide range of ages. In society, people are a wide range of ages.
You are not 'behind'. You are simply a few steps along a different path. You cannot compare yourself to other people on similar or other courses. These things are meaningless in reality, it's just that you can't see that from your perspective now.
You're thinking the way you are because for the last 10+ years you've been in this little sausage factory of education where everyone is in lock-step and in a familiar closely regulated system. Tertiary education isn't like that and neither is the rest of you life.