All sensible suggestions for you, LiteraryLark as to why your breast size has changed and will continue to change. You're in your mid-20s, so your breast size will continue to change.
Here's two helpful articles about why that happens to women. Could be related to your hormonal changes, weight change, medication, diet, stress, sedentary or active lifestyle, etc. there's a myriad of reasons.
https://www.bustle.com/articles/1686...n-your-20s-30s
https://www.womenshealthmag.com/heal...hange-with-age