Aww kylasbaby, such a tricky decision and one only you can make. Do you eventually want to settle down with someone and have a family together? I guess you are happy to go it alone as you are ttc alone, but I mean in an ideal world, what is your dream?
If it was me, because you are only 25 I'd focus on getting to know the girl you are dating and give the relationship a chance. In early pregnancy you can feel really rough, sick, exhausted, hormonal, moody spotty etc (as you might know from your mc pregnancy). In later pregnancy I personally felt very vulnerable, emotional, impatient etc. and life with a newborn is wonderful and amazing but really hard work. I just think all of this would put a huge strain on a new relationship and those first six months are usually the honeymoon period where you have the most amazing time together and if you were pregnant you wouldn't be able to enjoy it in the same way if you see what I mean?
I reckon you've got a better chance of your relationship lasting and having a baby together in a supportive, loving relationship if you wait a while. But also, there is never a right time and if you really really want to for it then do! It might take a few months to get pregnant anyway this time you never know (hopefully it won't though)
Good luck, congrats on your new partner and keep us posted on what you decide!!