Shania's High School Yearbook pic
Pics of her in her early 20's
A pic of her at the Deerhurst hotel, where she got discovered right before she went to Nashville
She definitely had large breasts when she was at Deerhurst, but there's a rumor that she was sleeping with the manager of the resort in exchange for gifts - including cosmetic surgery. She could have had work done then.
Its hard to tell her chest size from those other early pics, but I dont think she was flat-chested. Shania has said in various interviews that she was self-conscious because she had large breasts as a teenager. But she doesnt always seem 100% truthful in her interviews, either.
And finally, here's Shania at the ACMs this week. Her breasts do look quite big, and perky for a nearly 42 year old, and it wouldn't surprise me if she got a breast lift while she's been out of the spotlight for many months. She could easily have gotten work done since she's now often away from the public eye. I don't think she got implants recently, but a breast lift could be very possible.