Uncashed check from January- should I tell client before I cash it?

I found a check buried under paperwork somehow that never got cashed from the second week of January, should I still cash it? I was going to just let it go but my boyfriend thinks I should. The client is from is still an active client, I’m actually cleaning for her today but I’m embarrassed that I misplaced it for so long. If I do text her about it what do I even say? Thanks for any advice!