No. (: Not true. Tumblr lies.
”There was a rumour that Nagini was the snake Harry released from the zoo in Harry Potter and the Philosopher’s Stone. This was proven false, as Nagini is some type of viper while the snake in the zoo was a boa constrictor. Furthermore, the snake was given a male voice in the film, while Nagini is female.”
Also from a tweet “Nagini is NOT the snake Harry let loose in Philosopher’s Stone. That snake was headed to Brazil and Nagini was probably found in Albania”
Mhmm, take that crap out of circulation, psh.