Is it worth changing DD's name?

It's so common in my family I don't even know who is who anymore . My nan, gramp and all of my aunts and uncles on my mums side weirdly she is the only one who doesn't have a middle name go by their middle names not their given names.

I also have friend who goes by her middle name simply because her middle name didn't sound right as her given name.

I'd leave it!

Also in a worldvdominated by social media it'll be good for her to have a different 'professional' name for work and her everyday 'known as' name for everything else.

Do tell school which name to put on all her books and which you want them to teach her to write. We often have 'know as' children whose parents then say they want all labelling etc. to be in their official name and it all gets confusing. Some even change half way through the year. So 'David' suddenly becomes 'James'

It's quite common to be called by a middle name rather than your given first name. I'd leave it as is to be honest.

Leave it.

Loads of people are known by their middle name.

I know people that are always called byy their middle names. My mother, for example... I don't think there's anything weird about it.

If her full name is nice? I wouldn't change it.

DH uses his middle name on a day to day basis and it doesn't cause any problems, even at school he was known as his middle name rather than his first name. I also know a surgeon who goes by his middle name at work and for everything professional, it's only confusing in that his full initials are used as a hospital code, but the name doesn't cause any problems at all.

Change it.
At hospital/anything medical she will be called by her first name, disorientation even as an adult.
If she joins the police/law/armed forces she has to use her given first name. We know someone like this and it's difficult depending on the profession you choose, some you just cannot go by the "given" name. The person we know would change it if it wouldn't offend their parents.

Leave it. I know lots of people known by their middle name.

Many people are known by their middle name OP, I don't think it's a big deal, but by all means change it.
Personally, I'd leave it, her full name obviously sounds nice.

I knew a COLIN PAUL who was always called Paul

Didn't even know his first name til I saw his initials and DH told me his first name

Everyone just knew him as Paul

I know several people who are known by their middle name. It's not that uncommon, I wouldn't bother changing it.

Depends really - I know quite a few people who are known by their middle name, mostly fairly posh people who have been given family first names but are known by something else on a day to day basis

I would change it. She will face a lifetime of confusion and explaining.

You have the option to choose a 'known as' name at nursery and school, although this would probably be more usually 'Tom' rather than 'Thomas' for example rather than a totally different name. It could cause confusion or irritation in the future with an explanation needed every time ID is required but I have known people in similar situations. One girl at uni was Mary but bc said Jane her parents just changed their minds and called her a totally different name. It is your DD who will have most of the hassle in the future.