as your a newbie to this topic im afraid ill have to preach a bit... Pheidole are not suitable AT ALL for beginners. Workers and Soldiers alike are very tiny and masters of escape. Preventing that needs quite some experience. They are known houseants, meaning once they escape ( and they will bite through silicone, ytong and a lot of other materials) , they can settle down in your house and your facing a very high exterminator bill. Also they grow at an enormous speed, which doesnt make keeping them easier.
The colony can grow big and from the beginning on you will need possibilities to connect other tanks to the nest. Wouldnt know the age estimation for a Pheidole queen, but Lasius queens have been known to live for around 20 years.
Since i assume you're eyes got caught by the "soldiers": you wont find them fighting a lot. Usually, they transport bigger food or stones and bite through larger insects. The real soldiers are the workers. Also, dont be disappointed if the soldiers are smaller then most of your local ants.
To sum it up, you might be better off starting with an easier species. Did you have a look at Camponotus ligniperda or herculeanus? They grow very big and vary in sizes too:)