I certainly don't want you to purchase something that isn't right for you but I do not think these boots will be too small for you. We measured my foot last and it is between a 24.5 and 25 cm. and the boots are not too small on me. If you got the next larger size, there would be too much room in the shell, and the tongue would be the next range -- 25-26.5. You want the boots on the snug side compared to loose so there is no heel slip. You could always go to a boot fitter (preferably at a ski shop) and see what size they say would best fit you.
Please let me know if you change your mind. Thanks!