A few weeks ago, Tumblr user capybarad recently said "we need a tumblr-mumsnet cultural exchange programme" and I thought that was really fun. So if you'd like to meet some of us (mostly) not-mums get yourself a tumblr account!
Tumblr is obviously notorious for being the breeding ground for a lot of gender stuff (and you can totally go on trans tags to satisfy your curiosity), but it's also the place where I first saw a Magdalen Berns video. A lot of us (mostly) women in our 20s would love to have you!
Search tags like "radfems please interact" or "terf safe" to find people to follow as a starting point. If you want to find local women, search radfem with your city or country. Also enable messaging for your blog so people can chat with you.
"Reblogging" is basically the same as retweeting or quote-tweeting. Be sure to reblog things you like, it's how people find each other and if you follow someone but your blog is empty it looks suspicious and you might get blocked by someone who thinks you're a bot (imagine if a completely empty Twitter account followed you). So whenever you see something that makes you go "good point!" "smart argument!" "nice art!" reblog it.