Looks pregnant to me! Just a word of warning with guppies, once theyre old enough to give birth and theres a male present... Theyre going to be pregnant every 30 days or so and i think give birth to around 20 fry? Or i could be wrong... But either way theyll give birth every month. Some fry will get eaten, some may not. Chances are your population will increase quite a lot over the next few months, so either have a plan for the fry, or remove the females from the tank.
At 3 months of age a female is fully mature, she only needs to be in contact with a male once and can become pregnant every month or so for the next 6 months from that 1 contact. Guppies are also known as Million fish, you start with 6 and in no time have a million of them.