Floating Rate Mortgage?

Hello all,

Potential first time homebuyer here. I currently live in NYC and have applied for a mortgage through a local credit union. I've applied for a 30yr $350K loan at 6.625% . Upon closer inspection, I've found that the rate is a floating rate, not locked. It makes me a little uncomfortable that my initial mortgage payments could go up over time, but in all honesty I'm not educated on the subject. I'm interested to hear opinions on floating rates? Thanks.