We started talking online but we're finally going to meet each other
「web上でやり取りが始まって、実際に会うことになった」は英語で We started talking online but we're finally going to meet each other (for the first time)になります。We met and started talking online, but we're finally going to meet each other in real life for the first time でも大丈夫だと思います。
but - けど
met- 会った、出会った
in real life - なまで, 実際に
finally - やっと
for the first time - 初めて
Web上 - online, on the internet
やり取りが始まった - started talking, started communicating
イギリス 
