Is it normal for your second toe to be bigger than your big toe

Totally. Mine is. Someone said it is a sign of intelligence. I agreed.

Do you mean longer? If you did mean longer, the answer is that you can probably run faster than the average person can. Athletes have the longer second toe thing.
If you actually mean bigger... it might be a toe tumour and may lead to toe cancer - the deadliest of all cancers

It's common and normal

Quite normal, I've heard it's possibly more common in some ethnic groups than others but I don't know how true that is.

It's not exactly normal, but it doesn't matter either.

Both my second toes are longer than the big ones, and are also crooked from pointy toed shoes in my teenage years.

I read somewhere years ago that this was regarded as a sign of being a witch centuries ago, but if so there must be a lot of witches around, including the women in my own family..