Can't believe some of the horrible, cruel and thoughtless comments on here.
OP lost her mum at age 14, has a sister and dad she has no contact with and comes on asking for some advice around what is the biggest decision of anyone's life, let alone someone who has been through so much.
People having a go saying she's attention seeking and being pointless because she's said she's going to try for a baby - maybe she was always going to try but because she knows that the time is getting close she's very anxious.
I'm absolutely appalled that people think it's ok to be so nasty. I don't think op that people were being nasty when they suggested counselling etc, I think that's really good advice to be honest because it does sound like you have anxiety (you don't have to know you have anxiety or be unhappy to be anxious, but it can have a massive effect on your mental health especially if not treated with counselling or therapies)
But some comments are really too much, with nasty opinions of oh it's for babysitting purposes and why do you think we do our parents live far away 
etc. Can you imagine for just a moment what it's like to grow up without a mother??? Op is thinking what if that happens to her child, of course she is, she lived that experience.
Three days ago there was a terrorist attack where children have been killed and others left without parents. Of course the op is anxious about bringing a child into a world like this, where it sounds like she has already had such a hard time.
Some of the people on here ought to take a long look at themselves and instead of spreading the nastiness and bitterness that is oozing from your posts, how about treating people with a little love and understanding and kindness. Fine, you may not think it's a game changer for you, but everyone has different circumstances and levels of emotion.
Op, I really would suggest speaking to a gp about anxiety before you try for children. Therapy can make a world of difference and will likely help you in many ways, not just with this decision. I would honestly sit tight for a while, there really is no rush. 30 is young too and like others have said, doing training before kids is easier than afterwards. You've got your whole life ahead of you, even if you trained, worked for a year, took say, 8 years out until 1-3 kids were at school, you're still only around 35, with approx 30 years left to do the job you trained for. You would also have the option of part time work and further study when off with the babies. Btw I'm not trying to plan your life 
just offering another perspective. I tend to think of things very short term and sometimes that affects my decision making and not in a good way.
Good luck with whatever you decide 