"I guess I'm back to the same level now as I was in college."
"I guess I'm back to the same level now as I was in college."
"I guess ~" 「〜かな」
"I'm back to ~" 「〜まで戻った」
"the same level now as ~" 「今は〜と同じレベル」
"I was in college" 「大学のとき」
[これも](https://eikaiwa.dmm.com/uknow/questions/43680/)役に立つかもしれませんので是非クリックしてください。
After some years of blank, I started playing tennis again, and I think I managed to regain the level that I had back when I was in college.
ご質問ありがとうございます。
"After some years of blank,"＝「ブランクの期間を経て、」
"I started playing tennis again,"＝「テニスをするようになり、」
"and I think I managed to regain the level that I had back when I was in college."＝「大学であったレベルを取り戻せたと思う。」
ご参考までに。
オーストラリア 
アメリカ合衆国 
