somewhere along the line - Phrases/Idioms
The American Heritage® Dictionary of Idioms by Christine Ammer. Copyright © 2003, 1997 by The Christine Ammer 1992 Trust. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
At some point in time, as in Somewhere along the line I'm sure I climbed that mountain. [Mid-1900s]