I don't think it's strange at all. You're definitely in the minority, so you should probably be prepared for a lot of people telling you to have a biological child instead since it's usually easier, though.
This is not to discourage you from adopting, but meant to prepare you for how difficult the adoption process can be. My cousin can't have biological children because of health problems she had when she was younger, so her and her husband decided to try fostering and adopting children. My cousin and her husband fostered children for a while and made several attempts to legally adopt them before they were finally able to adopt a child--it was a long and very emotionally painful process. They were hopeful to adopt 3 more of their foster children, but their birth mother got them back (though she probably shouldn't have). It was heartbreaking for them. My cousin wants to adopt more, but as much her husband wants more children, he isn't sure that he wants to go through the process again.
Even going through an agency isn't very easy, so be prepared for what may be a long wait. This isn't to say I'm against adoption (I'm all for it!), I'm just painfully aware of how difficult the process can be.