Surely you can visit Uttrakhand in Jan or Feb.
As far as the safety is concerned, Uttrakhand is a safe place to travel. But you must also keep in mind that your safety is in your hands, so always be careful and book hotels and transportation from trusted sources or after thoroughly checking it. Have a happy and safe traveling !!
Yes you can visit Uttrakhand in Jan end of Feb. However the temperature is going to be really low around that time, there will be plenty of snow everywhere as well. So if you are fine by extreme winter conditions you can head there. Yes it is very safe for female solo travellers, all the mountains are safe for female travellers, a lot of girls travel solo in Uttarakhand
This is the best time to visit Uttarakhand if you love snow this would be the best time for traveling. And it is completely safe also as Uttarakhand claim to be one of the safest state for females travelers.