Since you have completed the event in the past, you would say,
I did my schooling at St. Xavier's.
You could also say it this way:
I graduated from St. Xavier's.
I don't agree with lina above because, if you were to say, "I went to school at St. Xavier's," that doesn't mean that you actually graduated, so such a statement could be ambiguous. My first rescript above using "did" seems to be implicit that you did graduate whereas my second rescript actually states that you graduated. I also do not agree with lina's use of the past perfect for the rescript of your second example. I would write it using the simple past:
I took my 10th Board (Exam) from there.
If you wanted to use the past perfect as lina points out, then context would be needed because the past perfect indicative usually means that that past event had occurred before another past event occurred:
I had taken my 10th Board (Exam) originally from St. Xavier's, but I didn't pass, so I retook it at St. Monica's a year later.
You have also created a comma splice above; rather than using a comma to combine these two statements, I would use a semicolon (;) if I were you:
I did my schooling at St. Xaviers; I (even) took my 10th Board (Exam)
I hope that might have helped you out. Take care and good luck!