updating my credit score on True Credit - a good idea?

No, you are not doing any harm to your credit by updating your scores. Moreover, requesting for a credit report is treated as a soft inquiry, not a hard inquiry.

For accurate credit information, you can pull your copies from https://www.annualcreditreport.com/ They are a part of the FTC website and trusted for accurate information.

No. It has no negative impact on your credit score because you are a consumer and you are simply reviewing your own credit report. But when you are making an application for credit it is known as hard inquiry. It shows up in your report and too many of such credit inquiries adversely affect your score. Usually a hard inquiry affects your score for around 6 months.