GDPR and DOB to register with a shop

GP2015

Hello,
I don't know if this is the right place, but ICO are useless for asking questions, I wondered if anyone can comment: I've just tried to log in to my (very old) account with an online shop that has spammed me mercilessly over the last 10 years (not that I mind, their spam goes straight to the bin). I logged in to my account and I was invited to update my consent due to, what else GDPR. What is alarming though is that they want my date of birth ( Requested by GDPR, Date of Birth:)
Now, I'm not an expert on GDPR, but I did have a look through that EU regulation, and the gist is, it's meant to protect individuals' data, rather than force them to give away sensitive information left, right and centre, particularly for something as petty as making a purchase in an online shop.
I do realize I can make up any DOB, or I can just go shopping somewhere else (life's too short), but somehow, this did get to me. I would be grateful if anyone could confirm if their demand is legitimate or just "because GDPR".

Regards,
n.

discat11

Provided they can identify you by some other means from the data they already record, there is no need to ask for anything additional than log in details at best.
If they don't already have your DOB on record then there is no pit t asking for it to provide an ID confirmation. GDPR does not 'request' anything specifically.