Hi Jol
From the description of your problem, both Invisalign and braces are suitable tools for closing the gaps that has opened up.
You will need to consider the pros and cons of the 2 different treatment tools.
Invisalign:
Pros:
1) More comfortable
2) Removable, hence no restriction in terms of eating
3) Easier for oral hygiene maintenance
4) Virtually invisible
Cons:
1) Higher cost
2) Patient compliance is crucial (optimal wear of 22 hours per day)
Braces:
Pros:
1) Cheaper option
2) Fixes to teeth, hence minimal compliance needed
Cons:
1) Less aesthetic
2) More painful
3) More difficult to maintain oral hygiene
Do consider these points before deciding the best option for you.