At 3 my son hadn't had any sort of soda.
At 3 we discovered that he has a serious problem with corn syrup, corn syrup solids, and high fructose corn syrup. That started a solid year of figuring out where all those things were hiding!
At some point between 3 and 4 we realized hubby has a problem with it too, and he found that his beloved Thomas Kemper root beer was made with HFCS. Off limits.
A couple months ago, I read the back of the TK rootbeer bottle, and it's now made with cane sugar/juice. There was much rejoicing!
And now, at just over 4, DS has had a little bit of Thomas Kemper root beer, and adores it.
Since you're in the UK, your sodas are very likely to NOT be sweetened with HFCS. In that case, I'm more OK with a 3 year old having it. And it will probably be really inexpensive (compared to if it were adults), b/c they will drink so little of it.
