You would need to apply to the court to become the guardian or conservator. However, if the power of attorney was properly drafted you will likely not have a need to do so.

A general durable power of attorney (GPOA) or Medical Power of Attorney (MPOA) is effective based on the terms of the document. Typically, it is effective immediately upon your mother's execution of the power of attorney or upon her incapacity. Once effective, as her agent you can exercise any of the powers granted under the power of attorney.

A guardianship or conservatorship on the other hand is a court-appointed position. Your mother nominated you, meaning she is recommending who she would prefer to have as her guardian/ conservator if one is needed. Only a judge has the power to make you a guardian or conservator - it is not automatic.

The difference between powers of attorney and guardianships/conservatorships is that so long as your mother has capacity, she can revoke the powers of attorney. On the other hand, once a guardianship or conservatorship is in place, the ward (the incapacitated person) loses their rights. So, for example, the ward may lose their rights to manage their own bank account or make their own medical decisions. As you can imagine, the standard for a guardianship or conservatorship therefore must be much higher.

Nevertheless, under Colorado law the judge must abide by your mother's preferences, unless there is a reason not to do so. That is, under Colorado Revised Statute § 15-14-310 the court must follow the priority of appointment. Under the statute, if no current guardian is serving, then the priority is a "person nominated as guardian...including the respondent's specific nomination of a guardian made in a durable power of attorney...."

In sum, if the GPOA provides you with the authority necessary then you will not need a conservatorship. Likewise, if the MPOA provides you with the authority necessary then you will not need a guardianship.

Please note that I assumed you general power of attorney was durable, meaning that it is not automatically revoked due to your mother's incapacity.