I was 15, everyone at school (in the uk) had phones. I remember waiting to be collected from school and reading the latest updates from the BBC WAP website on my Trium Mars phone - that’s a technology that’s long dead.
I don't remember if I got my first phone before or after this - I think maybe after, but I am honestly very unsure. I can tell you it was a 2nd hand 3310. Not everyone in school had one, because not everyone could afford it. Some people's parents didn't have them; most people's grandparents didn't. Landlines reigned supreme, and MSN whenever that arrived (still had a few friends without internet then, I was on dialup, a few people got broadband the year after).
I don't remember anyone using WAP really ever^. I don't really remember when mobile internet actually took off seriously but I remember a friend posting to facebook and getting updates via SMS in 2008/2009. Cool that you did use WAP, but you were likely a minority and that's nothing compared to the ubiquity of LTE connections of today.
^One of my friend's Dads worked for Vodafone at the time. Their HQ was commutable from where we lived. I discussed C++ with him a lot. I still don't remember anyone using WAP and they had staff discount, so your 12p/10p SMS was 2p for them. I only knew what WAP was because I read about it in PC Pro.
I think we had gone from almost no one having phones to the majority of the year having them in the space of that year. A lot of hand me downs from parents, and a fair bit of being envious of kids with Nokias.