It is very difficult to answer this question about only these specific accounts where there are more circumstances at play here. No lawyer can give you a reliable answer without looking at the will, the extent of your mother's property and who the "others" in the will are.
This answer is provided for informational purposes only. Actual legal advice can only be provided in an office consultation by an attorney licensed in your jurisdiction, with experience in the area of law in which your concern lies.
In some states you would be entitled to the entire estate. HOWEVER, be aware that the people named in her will could allege that you used "undue influence" to get your mother to put your name on the accounts ... I'm going through that with a client right now, and it's not pretty.
Also, be aware that if you were to get into financial problems before your mother's death, your creditors could drain her bank accounts because "legally" you are a co-owner.
Therefore, it's usually not a good idea to set things up this way. It's far better to have a comprehensive estate plan in place so that there are no questions.
The information you obtain at this site is not, nor is it intended to be, legal advice. You should consult an attorney for individual advice regarding your own situation.
The answer to your question depends on how she "put your name" on her account. If the account was titled as "Pay on Death" or "POD", then you are entitled to 100% of those accounts at her death. Those monies would pass to you outside of probate. Likewise, if you were placed on the account as "joint with right of survivorship" or "JWROS", the same rule would apply. If, however, she placed you on those accounts as "tenants in common", then you would only be entitled to 50% and your mother's estate would be entitled to 50%. Again, your 50% would pass outside of the will.
Unless there is some claim of undue influence or lack of competence, the monies that pass to you through these accounts never become part of the estate and, therefore, are not governed by her will.
The response which I have provided is not legal advice and does not create an attorney/ client relationship. Rather, it is only in the form of legal education and is intended to only provide general information about the matter within the question. There may be important facts that if known could change the answer. You should always seek competent legal counsel regarding any legal question you might have. Circular 230 Disclaimer - Any information in this response may not be used to eliminate or reduce penalties by the IRS or any other governmental agency.