How Do I explain bankroll management?

[Doc T River]

I just got some money for Christmas and my significant other is pushing me to use the money to buy into the $1/$2 blinds, $200 max buy-in no limit game at one of the local casinos. How do I explain that it would be a better investment to put the money into an online account and play 1 cent/2 cent No Limit.

One of the problems I face in getting her to listen is that she believes in me and my poker playing ability totally.