You can rebrand, really, at any stage that you feel your logo or your brand image is simply not representing who you are anymore.
In my experience, getting those two things in line is of the utmost importance. Your logo and brand identity is something that you deserve to be proud of and for that to happen, it must represent you.
You get a feeling instantly if it is right for you, and if that is the case, you will in turn, be more comfortable and confident showing it off.