Congrats and Good luck! I am whats considered a 'young mum' as well at 21 but are very lucky to be married to a wonderful man who loves us to bits I am due 27th Sept with a little boy, Jett.
Its not a tragedy to be pregnant in your early 20's, lots of women do it with or without partners and do just fine! Uni can be postponed and so what if your happy just being a Mum for a few years. Youve got plenty of time left in life to do all the things people think we youngun's with kids miss out on! I look at being a mother as just another wonderful thing life lets us experience, not as a burden or life-stopper! Keep that in mind and youll be just fine.
Look forward to seeing you around BellyBelly!