The te-form of a verb + よかったです means "I'm glad that I did something" or "I'm glad that it was the case".

<Example Sentences>

きょう　はやく　おきて　よかったです。

I'm glad that I got up early today.

*おきる→おきて(te-form)

きょう　すずきさん　に　あえて　よかったです。

I'm glad that I could meet you(Suzuki-san) today.

*あう→あえる(potential verb)→あえて(te-form of the potential verb)

*あう→あって(te-form)

パーティ　に　いかなくて　よかったです。

I'm glad that I didn't go to the party.

*いく→いかなくて(negative te-form)

きょう　じゅぎょう　を　やすまなくて　よかったです。

I'm glad that I didn't skip the class today.

*やすむ→やすまなくて(negative te-form)

References:

ば-form

https://anchor.fm/yuya-sato/episodes/-form-er8f82

Te-forms

https://anchor.fm/yuya-sato/episodes/Te-forms-enfaqj

Potential Verbs #1

https://anchor.fm/yuya-sato/episodes/Potential-Verbs-1-eoqaoi

Potential Verbs #2

https://anchor.fm/yuya-sato/episodes/Potential-Verbs-2-eorp21

Instagram:

https://www.instagram.com/yuyaman1986