I'm just wondering if both tenses are acceptable in the following statement. Does it make a difference to the statement?
I have loved trekking since I was a little boy. My dad used to go trekking with me when I was young and when I became/had become old enough to trek on my own, I trek on every Saturday or Sunday.
You would use past perfect if you were saying something like:
When I had become old enough to do that, I did X
And you are, but you have your tense on the second verb messed up:
... when I had become old enough to trek on my own, I trekked (simple past) on every Saturday or Sunday.
But this somewhat implies you no longer trek. You have a couple of options if you want to express that you still are currently trekking
... when I had become old enough to trek on my own, I trekked on every Saturday or Sunday, and still do today.
... when I had become old enough to trek on my own, I { started | began } trekking on every Saturday or Sunday.
Either started or began will make it clear what is happening.
Additionally, the word trek to me is a somewhat "off" in the way you are using it (it's not commonly used as a verb, for starters, but possible). It's more or less equivalent to going on a journey which is a major event. There's no set time a trek or journey must last, but it wouldn't be something you do once or twice a week normally. I'd use explore or walking, etc.
