If I become Power of Attorney of mother and control her finances, will Medicare look at my assets when she has to go into a nursing home?

thanks, she does not have much and hasn't for years, i just need to be there won't be any negative impact on my finances.

Nope. Hers alone - you don't Have to supplement her income either. Medicaid in FL (d/k where you are, states may vary but probably similar) means income not more than $2,000/mo and assets ($, stocks, etc) not more than $2,000 - yeah ouch, what's that today?
Anyway, you can prepay funeral needs, do other spend-downs for her, and I'd work on it NOW, rather than when she Needs it suddenly. Gifts and so on are subject to "look-backs" but again get that limitation clock Ticking so there is less discount on the funding for them.
We have a program called NH Diversion (aka project independence) which is to keep them from having to go to nursing home (they can age in place at ALF instead & Medicaid still pays for much of it)
Smaller ALFs are better (more hands-on care, indiv. attention, fewer really Sick people) happier places. And many of those do Daycare so that Medicaid pays almost ALL of that tab. My clients typically have No out of pocket for daycare which includes meals, meds administration, primary care Dr mnthly, podiatrist every 2 mos, activities and much more, even a shower 3 or 4 days a week.
Hope that helps - starting to plan sooner is best, good luck

Medicaid will not look at your assets. They WILL want to ensure that none of your mom's assets have been transferred to you or others. That means they look for transfers of money, checks, ownership of property, vehicles - any other substantial valuables. The system is designed to ensure that an assets are not transfered immediately before an application is made. The state doesn't want to be taken advantage of any more than the rest of us.

There are many articles and discussions about medicaid in the money and legal section of this site. Best of luck