Hum... Not really dude. When I got mine from a half inch fry she hit 12 inches in 11-12 months! They grow big really fast and they are very active. I had mine in a 5ft 90 gallon which she grew out of in less than a year and she is now holidaying at the lfs as my 7ft tank is getting built.
Basically they will grow 1 inch a month.. So if it's 2.5 Inches now...your 55 gallon will last around 3-4 months tops without stunting the fish.
So basically dude, unless you can upgrade fast (and if you can wait and get the tank first) don't do it. They are vey intelligent and highly active a 55 would very quickly become a cell, which will upset the fish and you.
Sorry bud.