cut teeth
cut (your) teeth
[British, American & Australian, American]
to get your first experience of a particular type of work and learn the basic skills.
She cut her teeth on a local newspaper before landing a job on a national daily.
(often + on)

[TahlilGaran] English Idioms Dictionary ▲

cut teeth
v. phr.
1. To have teeth grow out through the gums.
The baby was cross because he was cutting teeth.
2. cut eye teeth informal To learn something very early in life; gain experience; start by learning or doing.
■ Used with a possessive, usually used with "on".
The professional ball player cut his teeth on a baseball bat in the sandlots.
Mr. Jones's company is building the new Post Office in town but Mr. Jones cut his eye teeth as a carpenter.

[TahlilGaran] English Idioms Dictionary ▲