Which TurboTax program are you using?
The TurboTax online web-based editions?
Or the TurboTax desktop CD/Download editions installed on your personal computer? If the desktop editions, which operating system are you using, Windows or Mac?
Yes, you can edit the amount, but only in the first place you entered it. For most people that is in the mortgage interest section.
Check here to see if you can edit your property taxes:
If you have business use of home, you may have entered your property taxes there instead, or in addition. If you can't edit the amount here, reply back and TurboTax can help you further.