According to cic you need to have 3 yrs income statements to sponsor mother. I hope you are asking about applying PR to mother. where as that condition is not there for spouse. when did you land. sponsoring parents is more lengthier process than spouse.
you can start with sponsoring spouse and bring mother on visit
Minimum Necessary Income requirement for sponsors of parents or grandparents
If you are sponsoring a parent or a grandparent, you must submit a Notice of Assessment or Option C print out issued to you by the Canada Revenue Agency for each of the three years immediately preceding the date of your application. The minimum necessary income requirement, which you must meet for each of the three years is equal to the Low Income Cut-off s (LICOs) plus 30% ,taking into account the number of family members for whom you are or will be financially responsible.
If you reside anywhere in Canada, other than Quebec, you may use the Federal Income Table below to estimate if your income is sufficient to meet income requirements to sponsor. If you have eligible co-signer (spouse or common-law partner) on the sponsorship undertaking, their income will be added to yours as a sponsor.
If you reside in the province of Quebec, you will not be required to submit an undertaking of assistance for the family members you are sponsoring at this time. You will be contacted by CIC when your sponsorship application is assessed. At that time, if you meet federal sponsorship requirements, you will be notified that you must submit an undertaking of assistance to the Ministère de l'Immigration, de la Diversité et de l'Inclusion (MIDI) of Quebec so that your income can be assessed.
