More accurately, Jupiter opposite your ascendant means Jupiter is crossing your descendant. That's the place of others, partners, and significant people in your life.
Your question prompted me to look at the times when Jupiter crossed my descendant. It happens every twelve years, so, assuming you're more than 12-15 years old, you can remember when Jupiter last crossed your descendant. What happened then? Did any significant people come into your life?
Every time Jupiter crossed my descendant correlated closely with a time when I met new friends, and not just any new friends, but people who became significant in my life. (I can't be entirely sure about the first time, since I was only two years old then, too young to remember, but I do have some lifelong friends who go back to that time in my life, and it's possible they came into my life then.) Most notably, Jupiter was on my descendant on my fourteenth birthday, making it part of my solar return chart for that year. A few weeks later, I started high school and met someone who quickly became my best friend, and it was an instant soul connection.
Since you have your sun right at your descendant, Jupiter crossing your descendant will also be a Jupiter/sun transit. Jupiter magnifies what it touches, so anything to do with your sense of self and long term personal development will be magnified then. With a seventh house sun, your personal development has much to do with relationship to others, so those are intertwined.