The "if" is key. The parent post does not indicate that their voting residence is in Massachusetts - they could have maintained a voting residence in Pennsylvania instead of switching to MA.
Voting residency requirements are weird because they differ from state to state, and can be very vague when it comes to maintaining residency. As far as I can tell, Pennsylvania's 30-day residence requirement only applies when registering to vote; as long as you maintain a voting residence in Pennsylvania, you can vote in subsequent elections as you do not need to register again between elections. According to Article VII of Pennsylvania's election code (qualifications of electors), however, you lose your residence if you move to another state AND do not intend to return to Pennsylvania OR you move to another state AND intend to make it your permanent residence. So it depends on the parent poster's intentions of whether they view MA as their permanent residence or they don't plan to return to PA.
Voting residency requirements are weird because they differ from state to state, and can be very vague when it comes to maintaining residency. As far as I can tell, Pennsylvania's 30-day residence requirement only applies when registering to vote; as long as you maintain a voting residence in Pennsylvania, you can vote in subsequent elections as you do not need to register again between elections. According to Article VII of Pennsylvania's election code (qualifications of electors), however, you lose your residence if you move to another state AND do not intend to return to Pennsylvania OR you move to another state AND intend to make it your permanent residence. So it depends on the parent poster's intentions of whether they view MA as their permanent residence or they don't plan to return to PA.