Brings back memories. I (who grew up in a two-child family) had four children within 5-1/2 years, and yes, it keeps you busy. And tired, too. (Now I'm a grandmother.)
However, in my experience it was more difficult making the adjustment from one to two children than from two to more than two. You already know how to manage a plural number of children! It's actually not such a big leap after that.
To raise a larger family, it seems to me you need two things especially if you can get them. One is a good system of organization, which you will fine-tune along the way. The other is a supportive, uncritical husband.
When I was in the having-the-children department of life, it was quite looked down upon to have a large family. No woman was supposed to have, or *want*, more than one or two (if that), and I was not always treated with respect by others. Now many of the young families I know have several children - both through birth and through adoption - and it's nice to see. These families manage quite well, too.
I am so thankful for all my kids! I have never regretted having any and all of them, and wouldn't have minded more. But please - you're not in competition, really, with your relatives or friends! And you don't even know if another child will come. Refuse to be pressured; stop and breathe - take a nap - take your time and think it through. Any child, boy or girl, whether in your family now or to come, deserves to receive open arms and some degree of confidence.