I would do Network+ first as there are some parts of Security+ that assume at least a basic understanding of routing, firewalls, VLANs, etc.
The theory is you would do the A+, Net+, Lin+ prior to Sec+.
I have fellow students that were pissed that they started out with network+ or security+ they wanted to start off with either A+ or a MS cert like 70-270 but again,the institute does'nt care about anything but money.
so would you say i am ready to take the linux+ cert now? being i got all 4 certs in the order i have them on my certifications field.