I think the incorrect pronoun shift would be the line "<span>before you adopt a pet". I think it should be before one adopts a pet. This is because the sentence started with "It is". The "you" made the sentence very confusing. The second pronoun should be singular, the pronoun you is often denoted as plural and not singular.</span>
The expert from Shelleys possesses all of the great romantic ideas such as nature, darkness, suffering,
etc..
