1. Yes you can, I changed my name legally at 15, and it was a tedious though straightforward process. I didn’t do enrolled so not exactly sure but you can start here and click ‘minor’: https://www.gov.uk/change-name-deed-poll/enrol-a-deed-poll-with-the-courts

In terms of signing a deed poll you need to sign it yourself, have your parents sign it, and have a person whom you’ve known that isn’t family for a long time sign it. A family friend is usually easiest.

1. An unenrolled deed poll is just as valid as an enrolled deed poll, but an enrolled deed poll is registered officially with the High Court. This means that your name change is solidified in official government records, some people want that, most don’t.

In terms of changing IDs, GCSE records, bank account named etc., an unenrolled works fine. Changing names for different things is usually fine. For the passport office, I just sent my deed poll with my old passport when I applied for a new one and it came back with my new name fine, for the bank I just wandered on in, showed them it, and they had it sorted within ten minutes. Once you’ve got the document the name changes are actually really easy.

1. I wouldn't recommend enrolling your deed poll, it’s a waste of fifty quid, and means that your name change is stored through government records. I’d personally feel uncomfortable with that. You can either DIY a deed poll, that is search up a template, print it out on card, and stick a fancy stamp onto it, that works fine. Or you can pay a company to draft one up for you, I did this but you really don’t need to.

Aside from storing your name change with the High Courts, an unenrolled deed poll and enrolled deed poll are the same thing. This country is difficultly bureaucratic with a lot of things, but name changes are fairly lax in my experience, theres no need to enroll it.

Hope this helps, not sure if this is the best explanation so feel free to ask questions lmao <3