What زهراء mentioned is a good idea in your case. Have the Nikaah yet continue living separately (just visiting) until such time as you are financially stable. That way, you avoid falling into Haraam and in addition to that, you've "captured her" and no one else can now come along and marry her before you, so that worry is gone too.
Fitnah is rife in the world today. All over the world; it's not just in the West. For that reason, it's more advisable that youngsters get married as soon as possible, to avoid falling into Haraam. People will tell you to wait until you're older (maybe mid 20s), but their advice is based on what is more beneficial in terms of the Dunyaa. Getting married earlier is to benefit you in the Aakhirah, by saving you from Haraam. So you have to choose which is more important.