Helping my Daughter move out of the family home

This is my first time posting and I desperately need help in how to support my daughter who is leaving the family home.
We found a flat available that is literally 2 minutes from home. It has a spare room so we are able to sleep over if she needs us to.

We never said she needed to move out. I just happened to mention that it was availalble and when she saw the location she got quited excited about it and asked me to set up a viewing. We did that the next day and she really liked it and said she'd like to go for it.  She beat 4 other people who viewed it and the landlord picked her.  We had several days of excitiment about it and then several days of pure anxiety.  This is quite usual for her when decisions have to be made or we're going or doing something she's not sure about.
Now she's feeling quite vacant and unsure what she wants to do.

As a family we feel this will be a very positive move for her for her future development and I'm sure she will settle eventually and forge out a new normal for herself but I am under no illusion that it will be easy.

I know that whether she moves now or in 10 years time, she will experience the same level anxiety about it and of course we are not going to force her to move. It has to be her decision but we need to know the best way to encourage, support or advise on the situation.

Really hoping some of your lovely people will be able to offer some constructive and useful advice.

Many thanks in advance xxx