Learn Italian: Ieri mi sono annoiato alla festa. - Yesterday I got bored at the party.

The dictionary verb here is annoiarsi, meaning "to get bored" (literally, "to bore oneself"). Because it describes an action you do to yourself, it is a reflexive verb. In Italian, all reflexive verbs must use essere (to be) as their helper verb in the past tense. So, you must use mi sono instead of ho.

If a woman were speaking, would the sentence change?

Yes! Because we used the helper verb essere, the past participle (annoiato) must change its ending to match the person speaking. A male speaker ends it with -o (annoiato), but a female speaker would change it to an -a, saying Ieri mi sono annoiata alla festa.

Can I change the word order and put mi somewhere else, like after sono?

No, the reflexive pronoun mi must come right before the conjugated helper verb (sono). In the past tense, you always keep the pronoun and the helper verb together: mi sono, ti sei, and so on.

Why does the sentence use alla instead of just a la for "at the"?