Ah, sorry, I misunderstood. Are you introducing both languages equally, or does she have a dominant language that she has more exposure to?
If you have a multi-lingual parenting community, they might have tips about local resources and potentially be able to, after getting to know you and your DD in person, give you an idea of where her development is in comparison with real-life children in multi-lingual families. I've found that a lot of health visitors, etc, have single-language development as the basis for their advice, and that doesn't always translate to multi-lingual development - eg there's less code-switching needed.
What's your DD's language development like in general? Does she seem to understand single words, and is her comprehension roughly equal in both languages or does she have one language where her understanding seems better? When you say she has 4 words, is that in both languages or just in one? If she has the same 4 words in both languages, I'd be tempted to consider that as being more like having 8 words than 4 in practice. Or, does she have different words in the different languages? For example, our DC has some things they understand in both languages but only say in one (like "milk" - they understand the English word but only say the word in their other language).
We play a lot of games focusing on simple words in DC's 'second' language (we live in a predominantly English speaking community, so we accept that English is the primary language to which they're exposed, regardless of what happens at home and with family). For example, 'Give or No Give' (approximate translation) - one person has an object and can then choose whether or not to give it to someone else, usually with either praise for sharing or laughter at "No Give!" It's simple, fun, and focuses on one aspect of an instruction so can then be applied in real life.
If you can, I think it could really help to spend time together within a multi-lingual parenting community, where you can get a feel for where her development needs are as a bilingual child, which will be different from a child only learning one language at a time. It can be stressful if your main sources of comparison are children who can focus on just one language, as it's common for multi-lingual development to take longer and be less predictable or uniform.
If she's sociable, engaged and curious about the world, I'd probably just give her a bit more time and exposure to her languages if you can. If you have a good health visitor, they might have some resources, and you could try your local library too - ours has a section for 'Community Languages' which has some books in DC's 'second' language.