Answer
Salam Dear Sister,
Thank you for your question and for contacting Ask About Islam.
We pray to Allah the Almighty that all our dreams will come true one day.
You should be grateful to your parents who gave a good education in spite of the circumstances you explained in your question. Being simple is not a shame on your family. Simplicity reflects the pure nature and innocence of your family.
You mentioned that you had a terrible childhood and tough time. However, you still have hope for a better future. Sometimes the difficult times we go through encourage us to be better and look for better chances in life.
We cannot blame your parents for the unhappy life of your sister and your cousins. Maybe they did not choose the right person to marry.
Do not let the bad conditions of your sister and your cousins frighten you. You still have a better chance to choose the right person.
As for the issue of your wish to have a stable marital life, there is nothing wrong with this from an Islamic perspective. Dreams and wishes are natural feelings. We all wish for better jobs, better houses, better salaries, etc. What we wish for always comes to us in our dreams. Our advice for you is not let your dreams and wishes affect your life decisions.
You should busy yourself with being a good Muslim girl so that everyone can wish to have you as his wife. Embrace Islam in your daily life. Be a good model for other Muslim girls. Always think of how to be a good wife for your husband and how to be a good mother for your future kids.
Always remember that a Muslim woman is not allowed in any way to have any relation with any male friend outside marriage. Your communication with your university friend should be limited to the minimum and to necessities. Pure love is allowed in Islam and it is a natural feeling to feel emotionally attracted to someone. But Islam has put some guidelines to man-woman relationship.
You have to abide by these rules and regulations. You are not allowed to be in one place without a third party. We highly advise you not hide anything from your parents. Their experience in life will open your eyes to things that you cannot think of at this early age.
Do not let your wish lead you to do something forbidden with your male friend. If Allah has destined him for you, his admiration for you will increase. If Allah has not destined him for you, you are still in the safe side because you did not anything wrong with him. I think my message is clear.
The Prophet (peace be upon him), told us in many Hadiths about the characteristics which one should look for in a spouse. Abu Hurairah (may Allah be pleased with him) quotes the Prophet (peace be upon him), as saying:
“A woman is married for four things, i.e., her wealth, her family status, her beauty, and her religion. So you should marry the religious woman; (otherwise) you will be a loser.” (Al-Bukhari)
The same holds true for the qualities of the would-be-husband. He must be a good practicing and God-fearing 
Muslim. If the man you are looking for meets these qualities, you can pray to Allah to help you marry him.
While wishing for a good marital life, always renew your intention and make it purely to establish a good Muslim family which will contribute greatly to the wider community. Put pleasing Allah and the Prophet (peace be upon him) in your list of priorities.
You can always make dua to Allah to help you choose the right husband. You can say: “O Allah, grant me a good husband.”
You can also pray to Allah saying:
“O Allah, if in Your knowledge, my marriage to this man is good for me both in this world and in the Hereafter (or: in my religion, my livelihood and my affairs), then ordain it for me, make it easy for me, and bless it for me. And if in Your knowledge, my marriage to this man is bad for me and for my religion, my livelihood and my affairs (or: for me both in this world and the next), then turn me away from it, [and turn it away from me], and ordain for me the good wherever it may be and make me pleased with it.”
After all, if your wish to marry a certain boy does not come true, you have to accept it and be content with it. Allah chooses what is best for us. So we have to accept what Allah has destined for us. Being content with what Allah wills for us brings us always closer to Him.
Finally, we pray to Allah to help you choose the right mate and help you build a good Muslim family.
Salam.