yes, it's called a partial boil...
be careful, you won't be able to boil the full amount that the pot can hold. leave at least 2" for the foam from the hot break, stand by with a squirt bottle of water to control the foam...of use some foam control drops...
my first brews were in a 2.5 gallon pot...
good luck and welcome to the addiction of home brewing...
Woolly Bugger Brewery
Consumed:#2 Hefeweizen, #3 SoHo Brown Ale, #7 Belgian Wit, #9 Belgian Amber
Bottled: #1 Trout Belgian Trippel, #4 Smoked Porter, #5 Apfelwein, #10 Bell's Brown Ale Clone, #11 Belgian Wit, #8 Wee Heavy
Secondary:#6 Trout Belgian Trippel
Primary 3: Empty
On deck: ???