As a matter of elder care planning, you ought to consider the purchase of long term care insurance. It may be too late. Discuss that issue, however, with someone before taking steps related to guardianship. A guardianship would most likely be a negative factor in determining eligibility for long term care insurance. If your company will let you add her on your policy, that's great, but is she not already on Medicare? Medicare is probably the most cost effective insurance for an elderly person. As for guardianship proper, many of the same benefits can be achieved through the much easier process of executing a durable power of attorney. Whether a DPOA can meet your goals depends on particular circumstances. To get a guardianship, you really need to see an attorney because the process is detailed and requires a court hearing.
The decisions you make now will have long term consequences. I highly recommend that you see an elder law practitioner to discuss your mom's elder law and planning needs, including her will, durable power of attorney, health care power of attorney, and planning for financing of long term care costs.