Subjunctive - tener

The examples make sense of using, ex: tuviera, because the subject “had” something in the past. However, I’m confused by the test question because I don’t see a reference to the past. The sentence is “I hope i have a son by the time im 33.” I understand Ojalá triggers the subjunctive but I don’t see the connection to the last and therefore don’t understand why “tuviera” was the correct answer. I only selected it because it was the only subjunctive response.