You can still go in without student finance - you should apply ASAP, as SFE work to assess everyone for the minimum amount initially to ensure as many students as possible have something when the academic year starts. If you're entitled to higher means tested maintenance loan amounts these will continue being assessed after your initial SFE confirmation (they will revise the amount upwards if you are entitled).
You should submit your application now to get it started ASAP, if you haven't already. You may still be able to have it assessed for at least the minimum before the start of the course before degree programmes start (as they ordinarily begin at the end of September/beginning of October).
If your SFE funding isn't in place at the beginning of your course, you just need to notify the uni you have applied for SFE funding but it is still being assessed. They can flag this on their system so they won't expect you to pay out of pocket (at least, not immediately). You'll have to figure out your own costs for that time before your maintenance loan comes in if that is the case though - most universities have hardship funds which you may be able to apply to for support from a temporary loan from the uni in that case, although it's not guaranteed. It's better to apply now and hopefully have everything in place to start with.
Note this assumes you are a home fees student who is entitled to at least the minimum of SFE funding i.e. you have not had any prior study at degree level etc. If there is a question whether you are eligible for SFE funding in the first place this might complicate matters if you start the course but then are not awarded funding. Assuming you're a UK student who has been resident in the UK for the last 3 years and hasn't studied at uni before though you should be entitled to something.
Note that SFE can't advise you whether to start your programme or delay for a year or similar. They can only provide information on their own processes.