The information you provided is inadequate to determine which Pokemon shall move first. The speed stat is not determined by the base stat alone, but a variety of other factors too.
The net speed stat is determined by the formula:
(Base stat)level/50) + (IVs)(level)/100 + (EVs)(level)/400
The Girafarig likely had EVs and IVs which allowed it to outspeed your Floatzel. Or it may be using a Choice Scarf, or may have used a speed-boosting move such as Agility.
You should learn about EVs and IVs if you don't know about them already