I often hear these mistakes made by German speakers who are learning English.
They say: I have started to learn English 5 years ago.
There are a couple of things wrong with this.
Firstly, remember the word ‘ago’ is a key word for the simple past tense. It represents finished time. So instead of saying ‘have started’ just say ‘started’.
Also native speakers are likely to use the _ing form after the verbs to start and to stop.
Correction: I started learning English 5 years ago.
Some further examples:
He stopped smoking 2 years ago.
They started working at 7.30 in the morning.
She stopped skiing after injuring her knee.
Have fun learning English!
Louise