Your first solo train ride feels huge because it is. You found out you can get yourself somewhere.
STILLNESS
STILLNESS
Doing something alone for the first time changes what you know about yourself, not only what you can do. A solo trip is tiny in practical terms and large as evidence: you read the board, you got off at the right stop, you handled the few minutes when you were not sure. Proof like that is hard to get any other way, and it does not wear off.
Find one errand this week you would normally do with company and do it by yourself. Work out the route rather than being driven to it. Then keep the fact that you managed it.
Where was the first place you got yourself to alone?
Free, with nothing to buy inside it.