<human>: I apparently "look young". I am nearly 30 years old, I am married, I own properties, I drive a very boring "dad" car, I have credit cards and I speak politely to shop assistants and bar staff, but I am constantly being asked for ID to buy even the most banal of age restricted products. 
I have been asked to prove my age to buy alcohol, cigarettes, scissors, matches & bbq lighter fluid and even a pizza cutter (apparently it is a blade?!).
I want to know what I'm doing wrong. I look in the mirror and I see my 29 yr old self. I know I'm an adult- how do I know if one morning I wake up and "look young"? Do I have to wait until I have grey hair and a walking stick before I can stop carrying ID around with me?
I keep being told now that stores' policies are now "Think 25" or "challenge 25", so I have to apparently look 25, which is what exactly? I definitely look over 18, and have the wedding ring, car and credit cards to back me up- what thought process is going on in the head of Mr and Mrs Retailer here?
Do stores give any training on guessing ages of potential customers, or is my ability to pop to the shop and get a bottle of wine on the way home just pot luck?

Can you condense the text into a few key points?
<bot>: I look young despite being an adult. What makes you ID people? Please don't say "having a young face" as that doesn't really add anything here. Thanks!