Congrats for your A+
If you opted for Linux there should have been some thoght process behind it. Isn’t it?
I know a golden rule “Being a Master in one’s field earns you”
If Linux is what interests you go for it witha bang. Specifically, go for Red Hat Enterprise Linux and get your RHCE. Believe me there are few RHCEs as compared to MCSEs
Either is good, depends on what interests you.
But in general, linux field doesnt care as much about certs as the windows field.