Why wait if you know what you want?
The short answer:
What you want will still be there in a few years from now. However the life phase 18-25 will only happen once. Embrace it, enjoy it, if you do it right it will be the times that you look back on together when you’re older with a smile and nostalgia. You will also be better parents later, with more emotional maturity and greater financial stability.
The long answer:
You’re asking whether 20 is too young to marry. You should be asking whether 18 is too young, since she is even younger than you are. In almost all circumstances, I would say you are both too young. The only exception could be if you live in a culture where she needs to marry to leave her parents house. Even then, she should be cautious, because in cultures like that a marriage could end up trapping her more. You may not intend to trap her, but if divorce is taboo in your culture, that taboo is generally even stronger for women, and it is a risk that you should protect her from.
What concerns me more than msrriage is your talk about wanting to start a family. You’re definitely both too young for that to be a good idea, either for you or your kids.
If your relationship is strong, it doesn’t require a marriage licence, and there is no need to rush having kids. Your late teens and early twenties are formative years in which you will both grow incredibly. It’s an important period of independence from your parents during which you can explore the world and your place in it, but also a period to have fun and do crazy, silly, exciting things. Go to parties, go bungee jumping, go live and work in another part of the world for a year and visit all the neighbouring countries with the money you earn. Test your limits and learn about yourselves and each other. If the 2 of you can successfully navigate this life stage together, growing in parallel rather than apart, you will have an incredibly strong basis for your future lives together. If you can’t - which is sadly the case for many relationships - a marriage licence won’t save the relationship, and if anything could lead to feelings of being trapped, regret, and ultimately resentment. I know that’s difficult to imagine in this exciting, head-over-heels in love phase of your relationship, but that’s the point - this phase will pass and only then will you find out whether this relationship can endure.
I know only 1 couple who have been together since highschool and are still happily married today in their mid 50s. They didn’t marry until their mid twenties and waited to have their child until after that. They’re one of my favourite couples and hands-down some of the best parents I know. Their relationship is lovely and they have raised a kind, thoughtful, independent child. They could successfully achieve this because they allowed themselves time and space to grow and experience the world, and had the financial stability and emotional maturity to raise a child well.
PS: This couple went to Paris for a year in their mid 20s, and I went to London for 2 years in my early 20s. I cannot over-emphasise what an incredible life experience something like that is. I expected to learn about the English - and I did - but I learned even more about myself and my home country, in a place where the unspoken, unconscious societal rules were suddenly different. I wouldn’t have missed it for the world.
I’m using a boox. I dislike their built-in library tools, but it’s just an e-ink android tablet, so I installed a simple launcher and download whatever apps I want, including Libby.