Whether or not there is any opportunity to submit the errata will depend largely on the rules of your institution. At some universities, there is a fixed time limit to hand in a thesis (such as 6 months after starting). In such a case, examiners may not be allowed to take into account any erratum submitted after the time limit (or else, any student who doesn't make it withon the time limit could just get around that by submitting the missing parts later as amendments). In such a case, I also wouldn't expect there to be any defined process for what the office where you hand in your thesis should do with an erratum.
Even if it is not ignored, I am not convinced preparing an erratum right after submission comes across as an invariably positive sign. In a way, it shows that you failed to finish on time and to decide at some point that some version, perfect or not, is the final one.
That notwithstanding, preparing an errata document for your Bachelor thesis might be beneficial for later steps where previous works you created during your studies might be taken into account, e.g. for Master study admissions.
In all, the number of mistakes you found is probably pretty normal. If you decide to hand in these errata in the first place, you do not need to worry that you will "reveal" how errouneous your thesis is; the degree of correctness will already have influenced your grade, while at the same time, a typical amount of minor mistakes for Bachelor theses has probably been expected and appropriately considered while grading, anyway.